If a botfly larva is not removed, it will continue feeding beneath your skin for 5 to 10 weeks before it naturally exits on its own to complete its life cycle. While the infestation is technically self-limiting in most cases, those weeks involve increasing pain, risk of secondary infection, and the possibility of serious complications if the larva dies inside you or is located in a sensitive area like the eye or ear.
What the Larva Does Inside You
The human botfly (Dermatobia hominis) larva feeds in a small cavity just beneath the skin, breathing through a tiny hole it maintains at the surface. It anchors itself using rows of tiny hooklets and rotates around its axis as it feeds and grows. This mechanical activity is what produces the symptoms most people report: sharp, sudden episodes of lancinating pain (especially at night), a crawling or movement sensation, and intense itching around the site. The lesion looks like a boil or furuncle, usually on exposed skin like the scalp, face, or arms.
These symptoms aren’t constant. They tend to come in sudden bursts, often at night, sometimes followed by fluid leaking from the breathing hole. As the larva matures over those 5 to 10 weeks, it grows significantly larger, and the discomfort typically intensifies.
How Natural Emergence Works
Once the larva is fully mature, it drops out of the skin on its own, usually during the night or early morning. It falls to the ground and burrows into soil to pupate into an adult fly. After the larva exits, the wound it leaves behind generally heals, though the cavity may take time to close and can scar.
So in a straightforward case, you could technically wait it out. But “self-limiting” doesn’t mean “harmless,” and several things can go wrong during those weeks.
Risk of Secondary Infection
The open breathing hole in your skin is a direct channel between the outside environment and a moist, nutrient-rich cavity in your tissue. Bacteria can enter through this opening at any point during the infestation. A secondary bacterial infection can turn the area red, swollen, and hot, with pus draining from the site. In some cases, a deeper abscess forms that requires medical drainage and antibiotics.
The longer the larva stays, the longer that opening exists, and the greater the cumulative risk of contamination.
What Happens If the Larva Dies Inside
This is one of the more significant risks of leaving a botfly alone. If you try home remedies like covering the hole with petroleum jelly or tape to suffocate the larva, it may die before it can work its way out. A dead larva trapped in tissue acts as a foreign body. Your immune system mounts an aggressive inflammatory response against it, which can produce a painful abscess, a walled-off lump of inflamed tissue called a granuloma, or a secondary infection that requires surgical removal.
In other words, a failed attempt to force the larva out by suffocation can leave you worse off than either professional removal or natural emergence would have.
Your Body’s Immune Response
Even without complications, a botfly larva triggers a measurable immune reaction. Your body recognizes the larva as a parasite too large for white blood cells to destroy directly, so it ramps up production of eosinophils, a type of immune cell specialized for parasites. In cases of prolonged or multiple infestations, blood tests show elevated eosinophil counts, raised antibody levels, and signs of systemic inflammation. Nearby lymph nodes may swell and become tender. Some people develop fever, muscle aches, and joint pain, particularly with species that migrate through deeper tissues.
Complications in Sensitive Locations
Location matters enormously. A botfly larva on your forearm is uncomfortable but relatively low-risk. A larva near or in the eye, ear, nose, or mouth is a different situation entirely.
When larvae enter the eye, either in the space behind the lens or burrowing through the retinal layers, they leave visible tracks of damage in the retinal tissue as they move. Even after the larva dies naturally, the resulting inflammation inside the eye can threaten vision. Prompt treatment is needed to prevent permanent damage, and in some cases surgical removal of the larva from inside the eye is required.
Larvae in the ear canal can cause pain, bleeding, foul-smelling discharge, tinnitus, vertigo, hearing loss, and even perforation of the eardrum. Nasal infestations produce facial pain, bloody or pus-filled discharge, nosebleeds, and loss of smell. In the mouth or throat, patients describe a foreign-body sensation, burning, intense itching, and severe coughing fits.
None of these resolve cleanly on their own. In sensitive areas, waiting for natural emergence risks permanent tissue damage.
Why Removal Is the Standard Recommendation
The CDC’s guidance is straightforward: if you have myiasis, a healthcare provider should remove the larvae surgically. This isn’t just a precaution. Professional removal eliminates the weeks of pain, closes the infection window, prevents the complications of a larva dying in place, and allows the wound to begin healing immediately.
Removal is typically a minor procedure. A provider numbs the area, widens the opening slightly, and extracts the intact larva. The key word is “intact,” because if the larva breaks apart during removal, leftover fragments can trigger the same inflammatory and infectious complications as a larva that dies in place. This is why professional extraction is preferred over DIY approaches.
If you’re in a remote area without immediate access to medical care, the larva will likely emerge on its own within weeks. You won’t be in danger in most cases, but you’ll be dealing with escalating pain, a persistent open wound, and the ongoing risk of infection for the duration. Getting it removed sooner shortens all of that considerably.