Yes, all the symptoms are related.
You may try over the counter gel like Dologel on the blister
in the mouth. It helps in relieving the pain and decreases the sensitivity so that eating becomes easier for you.
The other symptoms may need a course of simple antibiotics like Amox. This is a prescription drug. Please get it prescribed by your primary care
Take a multivitamin
capsule for a week for faster healing.
Drink lukewarm water for some days.
Your symptoms will subside by next 3 to 4 days.
I wish you speedy recovery.