I was performing anal play and used aquaphor as lube. now i have blood in my stool. should i be worried about infection?

It is not feasible to know without examining you. You may damaged the skin or anal mucus membrane with your nail. It will heal. If you must engage in such practice, use a gloved finger to protect damage from the nails. Get HPV vaccine. Wish you good health! Safe sex: https://www.hopkinsmedicine.org/health/wellness-and-prevention/safer-sex-guidelines

It is unlikely that the lubrication or the actual sexual act caused infection, but you certainly could have some areas of irritation or damage to the lining of the anus. If the bleeding persists, you should see your primary care doctor. Good luck.