Hi. Welcome to HEALTHCARE MAGIC.. I have gone through your query and can understand your concerns... As per your complain the lump on the roof of the mouth due to injury can either be a Hematoma formed due to rupture of any blood vessel as a result of trauma and it will be probably dark red to bluish in colour and it heals mostly by itself slowly as the blood gets disintegerated.. It can also be a Mucocele formed as a result of rupture of a minor salivary gland or its duct leading to spillage of mucous into the soft tissues forming a lump.. It can also resolve on its own and you can do concentrated salt water rinses for shrinkage.. You should avoid hot,spicy and hard foods to prevent irritation and take a soft and bland diet... In case if it does not resolve you should consult an Oral Physician and get evaluated so that he can rule out the exact cause of the lump and treat accordingly, and if the pretzel is found within the lump although the chances are less the first thing will be the removal of the same to prevent infection.. Hope this information helps.. If you find the answer helpful please give me a Five Star Review and click on found the answer helpful as a token of appreciation.. Thanks and regards.. Dr.Honey Nandwani Arora..