Itching and dark formation on penis shaft after homosexual intercourse. Problem?

hi i m 29 years old male. i m a bisexual person.a month before i had a sex with one of my friend by using condom. he sucked my shaft of the penis (and not the head) , sucked my scrotum and between my thighs. After 1 week i got itching and dark formation between my thighs and on my shaft of my penis. then a small group of blisters on my foreskin . A year back i got chlamydia and it got treated and cured. i din t sucked or did any sexual activity at other person. only he sucked my penis with condom and other part.even i din t not give any kiss also.what could be the problem. is that would be a yeast infection or any other STD diseases.