I got a bone graft and the membrane is exposed, should I be concerned? (Photos)

I really doubt putting gause or anything else over the site will make any diference.  If you have had implants  placed , ideally you should give up smoking and if this is not possible try to avoid smokling for a couple of weeks following placement  especially if a bone...

No, you don't have to see your dentist earlier. Your dentist can go back and regraft if necessary. Bone will grow in the hole but slowly. The bone graft helps the existing bone maintain its shape without heavy shrinkage.

It sounds like a portion of the graft may have dislodged with the stiches and membrane.  Most membranes are designed to stay in place for 4-6 weeks.  The membrane protects the bone graft and prevents the gum tissue from invading the graft.  You should follow up with your surgeon...