Hi there Young lady.
It is of no consequence whether you had sex with an older man or with your boyfriend or any other. What is important is that none of the contacts was protected! However, from your history, it does appear that it is not any STD
but some sort of pseudofolliculitis due to the shaving of the region. Please do apply a cream containing betamethasone-Fusidic acid
combination (fucicort is one name that comes to mind) & see if it resolves in some 48-72 hrs or gets better. Then, nothing to worry about. If it increases, then you need to go visit a dermatologist/venereologist. I dont know which part of the world you hail from & if you wish to indicate the same, can point you in the direction of a colleague. If you wish a more precise diagnosis, please upload a close-up clear photograph of the region but do so on the private & discreet 'ask-a-specialist' arm of healthcaremagic.com & address it directly to mois if you please. Do hope this clears the air for you. Do please practice safe sex!
Dr Praveen Rodrigues MD
Dermatologist, Cosmetologist, Venereologist
Vikram Hospital, Bangalore, India