Welcome to HCM!
I have gone through your question and see that you have a concern regarding a painful red sore on back of your tongue, noticed recently. you have been smoking
1.5 year back and now not taking any kind of substance. your blood tests are normal except high lipids
What I can say from my clinical experience that it is NOT a tumor
, please don't worry like this.To me it appears an infection of some minor salivary gland
under the tongue, which are extremely painful and make it difficult to eat food.
however, you should be seeing a doctor and get it checked, as they donot get better on their own in small time and pain is unbearable.
they respond greatly to antibiotics and pain killer. till you visit your doctor, you can put an anaesthetic gel on it to reduce the pain.
Avoid spicy and hot foods as they will irritate it more.
Hope the answer helps you
Feel free to ask more question.