How Can Intermittent Feet Itching With Spots Be Treated?

Hi, 3 months ago I was bitten in my feet by something (I even didn't realize what it was). I begun to feel my feet itching only next day. It was very itchy and I was staying for about one month, then almost disappeared. But it returns in periods (from one week to two weeks) and it still itches. I see some spots on both my feet. It doesn't come from any bed bugs since I know how it looks and feels like.