I have a small lump under my tongue like an alsore but doesnt hurt, is very red. its not in the tongue but floor of mouth. what can it be.

See your dentist: It could be a blocked mucous or salivary duct, mucocele or any other pathology or even normal anatomical structure. It is always recommended to check with your dentist or PCP and have it checked out.

Salivery gland: There is a small duct at the base of the tongue which allows for saliva to drain into your mouth. You may have irritated it. Usually these conditions self limit and resolve. If not set up a dental appointment for a more definitive diagnosis.

One possiblity: It is hard to say without seeing it but one possibility is there are salivary ducts under the tongue and sometimes you can get a stone that blocks the duct which can cause some swelling in the area. Sometimes these stones will pass but if too large they need to be surgically removed. You should see your dentist for an evaluaion