Hi.. Welcome to HEALTHCARE MAGIC.. I have gone through your query and can understand your concerns.... As per your complain sores inside the mouth of your daughter can be Apthous Ulcers or can be due to allergic reaction to any food or medicine, Viral infection like Herpes, due to throat infection etc.. I would suggest you to consult a Paediatrician or an Oral Physician and get evaluated and he can do a thorough clinical evaluation and treatment can be planned accordingly.. As of now you can give her Tylenol for relief from pain.. You can also do cool compresses over the blisters.. Application of numbing gel can help in providing relief.. Give her more of liquids and soft bland diet.. Hope this information helps.. Thanks and regards. Dr.Honey Nandwani Arora..