Throat pain weeks, voice ok, swallowing okay, red lump under tongue, little clear blisters in mouth/ throat. otherwise fit and feel fine.

Lump under tongue: You should see an oral surgeon... It may be related to vascular tissue... A hemangioma. If it was cause by trauma it would have subsided on its own. Good luck!

Lesion: Any pain, bleeding, or as in your case swelling should be examined to determine cause, especially if of more than 2 weeks duration. Important that you see your General Dentist or a specialist Oral Surgeon to diagnose the "lump" and determine whether treatment or observation is indicated. Please call your Dentist for an appointment.