Hello,
Welcome to the ehealthforum and I am really glad to help you out. From the symptoms it looks like an infected hair follicle causing folliculitis. Folliculitis is the inflammation of one or more hair follicles. The condition may occur anywhere on the skin. Apply warm compresses on the bump and keep the area clean by using topical antispetics. You should consult a doctor as you might need a course of topical or oral antibiotics/anti-inflammatories to take care of the same. If there is any blistering or scabbing of the ump, then herpes sores have to be ruled out.
In that case investigations like culture of the virus, direct fluorescent antibody (DFA) studies to detect virus, skin biopsy, and polymerase chain reaction (PCR) to test for presence of viral DNA need to be done.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care.