Rash? Skin Cancer? (photo)

The bug bite was most likely a co-incidence. Chronic inflammation seems to be a factor in the development of squamous cell carcinomas, especially of the oral cavity but basal cell carcinomas have not been linked to bug bites. 

You should be washing the area with light suds during your shower. You can get this from antibacterial soap, but even suds from shampoo should help. Often, I'll have patients use a small amount of hydrogen peroxide on the healing surgical wound itself to help remove crust. But being four days...

This is a very good question. A flap is tissue that brings its own blood supply with it. It can be a random flap which has a more unreliable blood supply or it can have a blood vessel running in the flap called and axial flap that has a more robust blood supply and thus more reliable. A...