Accidents happen, especially with puppies... being a baby he is not fully potty trained so any accidents that occur are of your error and not the pups. How old is he now? And how often are you taking him outside? If you are having regressions I would recommend taking him out more frequently than what you are doing now, and if you can't keep an eye on him he should be in an X pen or crate. Remember right after he plays he will need to pee and probably poop too... sometimes right in the middle of play! With my puppy I liked to play with him at certain times of the day so that he would poop if I knew I was going to be busy, he got into a routine so there were no surprise poops because I knew when he was going to go. As far as pee goes make sure you are using an ENZYMATIC cleaner, and take him right outside when it happens no fuss.