Hi.. Can understand your concern.. As per your complain and explanation of symptoms you are suffering from a condition known as APTHOUS STOMATITIS leading to sore mouth and gums along with formation of ulcers.. Discolouration of gums can occur as a result of hyperpigmentation secondary to inflammation caused with smoke.. As the contents added in meth while manufacture makes it acidic and it leads to wearing off the enamel layer of teeth making them sensitive as well as meth smokers have more tendency to clench their teeth causing wearing off of the tooth structure.. It causes dry mouth and inflammation and atrophy of mucosa leading to ulceration and pain.. I would suggest you to immediately stop smoking meth immediately as it will be deleterious to Oral health as well as general health.. You should consult a dentist and get evaluated.. Use desensitizing tooth paste twice a day, apply on all teeth and keep it for a minute and then brush with the same as it will help in relieving sensitivity.. Massage your gums gently using clean finger to stimulate blood flow as well as cell growth.. Drink plenty of water to maintain hydration.. Get necessary x rays done by a dentist and get treated accordingly for cavity fillings, root canal treatment,Scaling, capping etc as per requirement.. But any relief you can expect only after withdrawal from smoking meth... Hope this information helps.. Thanks and regards.. Dr.Honey Nandwani Arora..