What can a dentist do to fix the yellow along my gum line and clear and white patches on my teeth? (Photo)

First of all, a correct clinical analysis is necessary because in the photo you can not see the different discolorations. As for the yellow line in the gum line may be gingival recession and exposure of the root of the teeth (the cementum has yellow coloration), the options to treat the stains will depend on the etiology, it can be whitening, veneers, in case of recession, periodontal surgery.

It looks as if you bleached your teeth and the tray or strip did not go all the way to the gum line. Unfortunately the photo is not super clear so that is all I can comment on now.