After all on 4 implants gums are white. Is this normal gum healing since they were so badly infected?

Gums may appear white as a result of the acrylic pressure on your gum. This can be easily fixed by relieving the pressure by filing down the pink acrylic. Best to call your dentist to make sure this is in fact what is going on. Hope this helps!

It's typical for an implant surgeon to advise the patient not to brush until the first follow-up visit after the procedure. It sounds like you may have a surface of plaque or biofilm developing on the surface of your tissue. I would advise you to visit your doctor to verify.  

With an all on 4 type procedure the new prosthesis replaced both the teeth and the gums.  Usually in the temporary teeth, the teeth look like teeth and the gums look like gums, healthy light pink.  Sometimes some doctors choose to use a white material for the gums, this is not common and may not look right but you need to check that the white is actually your living gum tissue not the replacement gum.  Under the bridge 5 weeks after the surgery the gums should be healthy light pink in colour.