I Practice Anal Sex With My Boyfriend. I Dont Involved

I practice anal sex with my boyfriend. I dont involved to multiple sex partner. My condition is, my anus is feeling swolen and sometimes burning. whenever i had sex after days my underwear has shit stains. I felt like my anus was worn out. I have done research in terms of HIV but no symptoms indicated. Am i prone to HIV? Is there any tendency that my laciniate part has infections and may result to worst?