Hello - thanks for asking your question.
Without seeing the lesion it is impossible to say what it is. Here are several considerations.
There are many infectious etiologies that can result in genital lesions. Ulcers can be the manifestation of syphillis, herpes or chancroid. Each can be diagnosed with appropriate culture or blood tests and treated with appropriate antibiotics or antiviral therapy.
If the lesion is more raised, then the possibilities may be a genital wart, molluscum (caused by a virus), a raised blood vessel or folliculitis. The lesion should be inspected by your personal physician, urologist or dermatologist. If the cause is folliculitis or cellulitis, then antibiotics may help.
Again, without seeing the lesion, I cannot be more specific.
Followup with your personal physician is essential.
This answer is not intended as and does not substitute for medical advice - the information presented is for patient education only. Please see your personal physician for further evaluation of your individual case.
Thanks,
Kevin, M.D.