My tongue is very sensitive almost like it has been burnt, although no visible sores, but feels numb like it is covered with a film&tip slightly red. ?

Glossitis: This is from inflammation of the tongue . Causes include B12 deficiency, irritation from oral preparations, etc. Need to get checked by your doctor or dentist.

Sore tongue : Your symptoms are consistent with glossitis and can be caused by reaction to medication you are on or a condition known as geographic tongue You should be seen by an ENT specialist and possibly have a biopsy