I don't know the answer

Invisible biting insects doesn't tell us what kind of insects they are so it's hard to say how to get rid of them. But my guess would be, if you can't see them, even if you find a home remedy, you won't be able to get them all. I would advise you to call your local pest control company.

An exterminator is probably not your best first step. If you are being bitten, have a doctor examine the bites, as insects are not the only things that can cause skin irritation. Your solution may be as simple as changing your laundry detergent or as complicated as a treatment regimen for parasites.

Please see a doctor to determine the cause of your skin irritation first.