My tongue has been sore for over a week.  It is streaked with red and has many white raised nodules which are usually flat and pink.  There is almost like a crack in the middle.  It feels like I burned it and the feeling never goes away.  I do wear a small mouth guard at night that my dentist switched to one on my bottom teeth since it looks like I have been rubbing it on the mouth guard.  I have tried peroxide mouthwash, benzocaine applications with not much in the way of results.  My dentist also told me to take 1000mg extra of Vitamin C.
It can be a case of glossies -dermatitis, take bland diet, glycerin borax apply thrice daily, vitamin B complex forte tab 2 daily or in. B complex with B 12 1 ml I'm daily for 10 days, avoid spices, tobacco hot foods, smoking and alcohol. Take some systemic antibiotics to prevent secondary infection, if pain take paracetamol TDS, byte or McCoppin. If not relieved within 3 weeks then go to an ENT surgeon to rule out herpes labials, oral thrush and go for biopsy of the lesion to rule out any malignancy.