My 4yr old son has 3 staples in his head from a pool injury. Is it normal for puss to ooze out of wound?

I've kept it clean and dry but when i picked him up from daycare today it was matted and yellow. I brought him home and put him straight in the bath. I tried washing his hair with baby soap and blotting to clean it. It just keeps oozing yellow puss and some blood. And of course he says it hurts. I put a little peroxide on it but i'm still worried.