Slight pain, slight burning, some discharge after a few hours but no blood after anal sex ejaculated inside without condom, should i be worried?

Yes. Avoid friction.: Anuses are not designed for in-and-out sex. Just like in any big city, some streets are one-way and some streets are two-way. A vagina is created or evolved to be a two-way street (penis in, baby out). However, the gastrointestinal tract is designed to be one-way, with an opening on each end. Food goes in the mouth, and the brown stuff goes out the butt. (An exception is when one vomits.)

Use protection: STD's, especially HIV, can be transmitted through anal sex, so condoms are a must to protect yourself. The anal tissues are easily injured, and anal intercourse can cause bleeding as well as transmission of infectious agents. Best to be checked for STD's