How to tell if a cut on finger is infected?

Finger got cut, 2 small slashes. There are 2 flaps - the top layer of the cut skin that I left on, hoping it would seal up quicker. Now, 5 days later, it looks like a black spot and slightly dirty under each. Is it just a scab and the skin is healing, or should I cut the 2 flaps off and disinfect, start from scratch, etc?