What Causes Remnant Spots After Mosquito Bites?

It's been almost 3 weeks now since I've been bitten by a mosquito and the two spots (where I've been bitten) on my hand are still there. They aren't as noticeable as they were the first few days (red bumps) nor do they itch at all anymore, but now there are just two faint spots left. The marks are about an inch away from each other.

Normally whenever I've been bitten by mosquitoes they dissapeared completely within 2-3 days. Does anyone know what could be the problem or how to make them go away?

Also I'm positive it wasn't a spider or any other bugs because of the way they looked and itched, on top of the fact that the night before they appeared there was a mosquito in my room I never found before I went to sleep.