I Had 3 Surgical Extractions 3 Days Ago, An Impacted

I had 3 surgical extractions 3 days ago, an impacted wisdom tooth and 2 that were beside the wisdom tooth that were decayed. It was somewhat of a difficult procedure because of the decayed teeth being in pieces. I have had quite a bit of swelling the past 2 days and moderate pain. It is not at the extraction site but more so around it in my gums and cheek. Pain relievers seem to help with the pain though. I looked at the extraction site for the first time today and noticed a white-like layer over it. I was wondering if this was normal and what it might be. I also had dissolving sutures put in and I was wondering when they would dissolve. Thank you.