Hi Thank you for asking HCM. I have gone through your query. If you send a picture of the rash then it will be more helpful in identifying. From your description it can be genital herpes. Do you had any unprotected sexual intercourse. ?. Genital herpes comes in blistering rashes and will associated with burning sensation or pain and itching. Acyclovir cream for local application will be helpful for this. If it is more trouble some then oral anti viral drugs will be required also. You can also use ice water for washing. A consultation with dermatologist is well appreciated to confirm this. Hope this may help you. Let me know if anything not clear. Thanks.