Hi,
Noted your history about having itchy skin lesions on the leg and buttock crease, scab on the leg is dark and feels somewhat numb, incidentally coexisted with the first sex as per your history.
This looks to be related to the skin condition that gives scan and itching.
Hence I would advise you the following in such a situation:
First of all take an opinion of a
Dermatologist as applying anything can change the character of the disease hence making the diagnosis difficult.
Till then you can take an antihistamine to control the itching and will control any reaction.
You also needs to undergo the blood tests for
STD panel.
Do not apply anything locally till seen by the Dermatologist.
You can take pictures of the affected area that will help your Dermatologist and also help for followup.
Take care.
Hope I have answered your query. Let me know if I can assist you further.
Regards,
Dr. T Chandrakant, ENT & General Surgeon