I got bitten in September while sitting in a friends garden. Two small circles next to each other and then again further down my leg. It’s still itchy and sometimes swells up, starts to disappear then comes back. I thought it had finally gone a month ago then the other night I thought I’d been bitten again but it was the same bite! All big and itchy again. It’s so weird! What could’ve bitten me? The skin around it is fine