Hi.. Can understand your concern.. As per your symptoms and the sequence of occurrence indicate that you have canker sores or apthous ulcers as when they appear there can be tingling and burning of the mucous membranes a day or so before they erupt in the mouth.. The white spot that appeared under the tongue can be an apthous ulcer and bruising and burning under the lip indicates that there can be more eruption of canker sores on your inner lip too.. As you started smoking again there can be inflammation of the mucosa due to heat and chemicals present in the cigarette smoke and can be one reason for the canker sores to occur.. I would suggest you to stop smoking as it is a very harmful thing for the body and can be causative of serious diseases like lung and mouth cancer.. For the ulcers/ sores you can do warm saline gargles. Gargle with 1:1 solution of milk of magnesia and benadryl liquid can help.. Dilute hydrogen peroxide gargles also help. For pain relief Ibuprofen or calpol can be taken.. For avoiding discomfort during eating application of numbing gel containing lignocaine or choline salicylate over the sore can prevent discomfort.. Drink plenty of water to maintain hydration.. Hope your query is solved.. If you find the answer helpful please write a positive review and click on find this answer helpful as a token of appreciation.. Thanks and regards.. Dr.Honey Nandwani Arora.