HELP!!!

Chantel

This is far from mommy related BUT it does have to do with my furbaby. he'll be 4 month old tomorrow, and we've had him since he was 6.5 weeks old. the people we got him from told us that he had gotten fleas from being outside a lot, but we didn't think that it was THIS bad. we've been trying to get rid of them now since we brought him home. we've done flea bathes with Dawn dish soap, wash blankets regularly, we don't have any carpet in our house so that isn't the issue, just recently we tried one of the flea drops and it just made them multiply. I don't know how it happened, but he also has three different sores below his shoulders. We are just at such a loss and feel like we've tried everything... what is safe AND actually works?