Umbilical cord

My baby is 25 days old and his umbilical cord still hasn’t fallen off. It’s gotten wet at least twice that I know of and it’s had a pretty bad odor for at least a week. We’ve been keeping it as dry as possible and the stump looks completely dry. I don’t see any yellow puss coming out and the skin around the base is not hot or red; but there is some dried blood on his clothes sometimes. I’m just worried because it stinks and he’s almost 4 weeks old and it doesn’t look like it’s falling off anytime soon. We go to the doctor on Tuesday for a check up, but I’m concerned it might be infected.