Thank you for your question. Hyperpigmentation after surgery is a natural response to inflammation in some, but not all people. Technically it is called post inflammatory hyperpigmentation.Fortunately it is almost always temporary. However it can be reduced with skin bleaching agents, IPL or laser treatments in cases where it is prolonged.
Hyperpigmentation has nothing to do with the dressing. It is hard to give you adequate advice without seeing you in person. Surgery is not in exact science, not everyone’s results are the same.