How Can Cystic Acne And Impetigo Be Treated?

A few months ago I had a severe cystic acne breakout that came from use of a cosmetic product I was allergic to, improper care when cleaning my skin, and along with impetigo and an emergence of eczema on my face. I was given several antibiotics that actually drained my face and cleared the acne within two weeks, leaving PIH spots. These spots have since cleared up with use of Eucerin and I have yet to have more than one or two small pimples since then (and I ve been cleansing my skin better as well). However, there was a particular cyst under my eye that drained and has left a purple bruise that is not tender or itchy to the touch (feels like nothing is there and is not raised on the skin). I have light brown skin so the bruise-like scar is noticeable, but not stark. It hasn t faded since the wound healed. What is this spot and is there anything I can do to rid of it?