Hi.. Can understand your concern.. As per your complain first of all if the pain is too much you can use topical anaesthetic agents like Mucopain gel, they contain numbing agents and after applying the pain is relieved and you can eat and speak with ease.. If there is inflammation topical steroids can be used.. I would suggest you to consult a doctor first and get evaluated and then only any medication should be taken like doctor can also prescribe you vitamins, iron and folic acid if required in case of deficiency. If there is any infection associated with the ulcer then antibiotic could be prescribed.. If there is excessive pain Ibuprofen or Paracetamol (only in paediatric or children doses) can be taken.. All this can be taken after clinical examination by a doctor.. Other things what can be done are; Avoid spicy, sour, hard and hot food to avoid discomfort. Maintain a good oral hygiene, you can use an antimicrobial mouthwash to gargle like Chlorhexidine. Vitamin C candies and lozanges are available in the market, one taken a day can be helpful. Avoid citrus fruits as it can aggravate the problem. Brush your teeth gently using soft tooth brush.. YOU SHOULD TAKE ALL THE TREATMENTS ONLY AFTER CONSULTING A DOCTOR AS YOU ARE JUST 12 YEARS OF AGE AND YOUR MEDICINE DOSES ARE DIFFERENT THAN ADULTS SO ONLY THOSE DOSES AND MEDICINES YOU CAN TAKE WHICH ARE SUITABLE FOR CHILDREN LESS THAN 14 YEARS OF AGE. Hope your query is solved.. Thanks and regards.. Dr.Honey Nandwani Arora..