The best thing ive ever used is tea tree oil, i get bit all the time and they welp up. I used to buy Melaleuca's tea tree oil, i now use tea tree oil from walmart, etc, but doesnt work nearly as good as Melaleuca, theirs is more potent. going to have to find someone who sells it
Slap some rubbing alcohol as soon as you see or start scratching the bite. It will stop it from itching and will often make the bite marks go away. Trust me as someone who ended up with several bites that would not go away from many years ago. Hope it works for you too.