Same age kid bit my son when he was playing. What should I do moving forward?

My son, 5, was playing at his friends house and later his parents came to drop him off.They did not mention anything about the bite. Since my son is shy, he never said anything about the bite, but when I was changing his clothes I saw it and he said it really hurt. It is pretty red and badly bruised.Online it says you don't need to go to doctor and the wound can be washed, but I don't know what to do moving forward. via /r/Parenting https://ift.tt/2QmQ2cj