I've just had two teeth out, is this normal...?

I had two teeth out about 38 hours ago, it was agony. For a while afterwards I had toothache from the teeth that were around the 2 teeth taken out (the 2 teeth taken out were next to each other), now my gum just feels numb and swollen I suppose.

Where the teeth used to be, there's kind of a grey/white area inside the gum. Is this a scab forming or is it something more sinister? It doesn't hurt to touch or anything so I don't think it's infected I'm also pretty certain there is no tooth left in there, it's not hard to touch and the dentist triple checked to make sure she'd got it all out. I keep brushing my teeth and washing my mouth out with salt water to prevent infection. Is this white/grey stuff normal?

Thanks for any replies.