Hi.. Welcome to HEALTHCARE MAGIC.. I have gone through your query and can understand your concern... As per your complain it seems that there is inflammation of the labial mucosa leading to redness and burning sensation. It can occur due to common condition causing inflammation of mucosal surfaces of mouth known as STOMATITIS and can be due to few causes like Nutritional deficiency of Iron, Vitamin B12 and folic acid, stress, allergy, physical trauma etc.. Although the burning sensation of the inner side of lower lip alone and not involving any other mucosal surface is not a common finding although it is seen in a few syndromes like Sjogren s Syndrome or Raynauld s disorder etc.. But in case if you do not have any other symptoms these conditions are also does not seems to be a cause.. Nothing to worry, consult an Oral Physician and get evaluated and treatment can be planned according to the cause and if nothing specific is ruled out treatment can be symptomatic and is based on relieving the symptoms.. The physician can advise you to take a multivitamin for one month time.. Doing cold water gargles and sucking ice pops can relieve.. You can apply a numbing gel over the inflamed area for relief from pain especially during meals for preventing burning.. You can also be advised to apply a steroid based ointment for reducing inflammation.. Avoid hot and spicy foods.. Drink plenty of water to prevent dry mouth.. Hope this information helps.. Thanks and regards.. Dr.Honey Nandwani Arora..