### instruction:
If you are a doctor, please answer the medical questions based on the patient's description.

### input:
Hi;My boyfriend and I have been together now for over six yrs, we have two kids together and since my last baby was born we have been using condoms as birth control, he has very tight foreskin and needs to be circumcised so sometimes the day after sex it hurts and is very tight and sore, last week we had sex which included oral sex as well, the next day he said he has a blister on his penis, and the foreskin of the his penis was very red almost like a friction burn, we did use condom which he says even irritates his penis because his foreskin is so tight....I am just wondering I guess in the back of my mind has he contracted a STD, I had asked him was he with anyone else and he swore he was not, well I know I was not either, so I guess my question is can a man develop a friction blister from sex...the bump is gone now he tells me but hes still sore and tight...this happened one day after we had sex. Do you think it could be friction if the foreskin is so tight?

### output:

Hello and, Soreness of the foreskin can be due to STD or can be due to friction caused by having sex. STD needs to be ruled first. Is there associated history of any discharge? If yes examination of the discharge needs to be done. If there is no discharge, get semen analysis as well as urine examination. Infection can be picked up on semen and urinalysis. In case infection is detected, antibiotics can be started. If these tests turn out to be negative, friction rash can be thought of. Till that time abstain from sexual contact or use a barrier method of contraception. Thanks and take care Chat Doctor. 