I have a cavity on tooth #31 + tmj, noticed bit of flat raised gum behind it not sure if swollen, mild pain only on gum, tooth doesn't hurt, no sensitivity. don't have a wisdom tooth there. can only see a dentist in 1 week, is it safe to wait?

Perfectly safe. You may have a periodontal pocket distal to #31 where inflammation may have caused the gingiva to swell slightly.

Mild pain may indicate gum inflammation and/or food impaction. You can help reduce swelling by flossing 2x/day, every day, until you see your Dentist. Then once your problem is resolved, ask Dentist for specific Oral Hygiene instructions and follow them, all of them, every day.