White substance back throat, slight pain under chin, gums, and base of tongue when swallowing. Can see red veins back of throat. Cough at night, hoarse?

See an Oral Surgeon. See an oral surgeon who may refer you to an ear, nose and throat doctor. Do not wait, go now.
Need to see doctor. Your condition sounds serious. It might be strep throat, or fungal infection. It is better to see your doctor to exam and have throat culture and treat it accordingly.