Gum Graft

I had a gum graft done 4 days ago. Before the graft I was told this would be a relatively painless procedure. That it would feel like a pizza burn on the roof of my mouth. But I find it to feel more like someone took ripped a hole out of my mouth. So my two questions are. Is this pain normal? And how long does the roof of my mouth normal take to heal? And am I wearing my stent too much? I’ve been wearing it pretty much 24/7 since the procedure.