Vaseline is a good idea but Vitamin E oil is better. You can find it at the pharmacy or at Walmart. Use a Qtip to apply it only to the gums before and more importantly after whitening. Are you using trays? Maybe they don't fit well or maybe you are using too much gel. You need a very small amount of gel only on the surface that touches the front of the teeth.
Depending what do you want about your smile. Gingivectomy or so called :smile lift" will make your teeth longer and if you want straight, perfect teeth you can do veneers after that.
Find a dentist that can use laser to reshape your gums. Don't be afraid of the healing because you are diabetic. You will heal just fine. Don't let anybody convince you to do a scalpel surgery on your gums. You will heal slow and develop a scar tissue and its going to be worst. Veneers are an option only after reshaping the gums, so called "smile lift" and can't substitute for gum reshaping and they are more invasive and way more expensive. Good luck!
You don't have to worry , you have to do something. Visit a dentist and have an Xr taken to see the root of the tooth for possible infection. After an acute abscess it is quite possible for the infection to become chronic, meaning you still have an infection without having discomfort. If it is determined that this is the case having root canal done is the way to go if you don't want to loose the tooth. If the chronic infection is not treated it can cause root resorption and/or resorption of the bone around the root of the tooth. In some cases the acute infection can subside after the antibiotic and and actually heal. If the nerve of the tooth survive its all good, and if it does not it may die and the canal calcify. The only symptom in this cases is darkening of the tooth.
Leave them alone! From what I see in the photo your gums seems to be fine and your teeth with proper length, but your upper lip appear short because we can see the bone of the jaw not only the gums. Surgery in not very likely to help much.
