Maybe they are not bites and not related to anything in your surrounding or anything that u are able to control.
What im trying to say is are you really 100% sure that they are bites? I instantly believe you when you say that it looks and feels like you are being bitten. But when u cant find a clear source and cant see some logical pattern as to where/when u get bitten then its possible that you are not actually getting bitten.
There are enough skin conditions or other diseases out there that cause skin problems that look and feel like bites. While u are looking for some kind of pattern or special circumstances the "bites" seem to follow in order to control it, it might not follow any kind of logic at all.
Im not here to jugde you at all. Im merely trying to help out based on my own experiences. Its wise to keep an open mind on the matter because its a dark road your taking if you cannot look past anything else then something is biting you.