Hi..
Welcome to HEALTHCARE MAGIC..
I have gone through your query and can understand your concern.
As per your complain and presentation of symptoms bump over tongue that is occurring repeatedly on the same site and you have rotten teeth in same location there is a possibility that there are some irregular and pointed surfaces over the decayed tooth and
injury to the tongue is causing formation of a traumatic abscess.
The other thing is that you have a lump over the gums in the area of decayed teeth is probably a
dental abscess formed due to infection from teeth reaching the area below the root tips..
Nothing to worry,consult an Oral Physician and get evaluated and in case of pointed teeth surfaces get them smoothed..
For the ulcer over the tongue, do soda bicarb gargles, if there is pain apply a numbing gel containing Lignocaine.
Take Antiinflammatory painkiller
Ibuprofen.
Other thing is that get an IOPAR [ xray ] of the infected teeth done and in case if they can be saved
root canal treatment of the teeth followed by antibiotics and painkillers will relieve..
Hope this information helps..
Thanks and regards.
Dr.Honey Nandwani Arora.