Sounds like a bad fight. What happened? And that someone resorts to biting? Geez. But the good news is that even if he bit directly onto your skin and broke it and you were bleeding, you'd not be at risk for HIV. Saliva and air inactivate the virus. AND he bit through your clothing so there was no direct contact which it makes it even more of a zero risk (if that is possible). The only ways to get HIV are exactly as Chima7 has stated which is to have unprotected vaginal or anal sex or share IV drug needles. All transmission takes place inside the body only. So, rest easy and know you didn't have a risk. But try to stay out of fights.
This is not how HIV is spread. In an adult, only unprotected anal or vaginal sex and sharing IV drug needles with infected users could possibly result in HIV. Nothing else, including a bite from someone, would cause someone to have a risk.
If your skin wasn't broken then it's not a risk the skin was still intact as your describing and the only fluid you came to contact was saliva and it's non transmitted through saliva