Accelerated 5 day radiation problems

I had surgery for invasive ductal breast cancer on Aug.  The pathology couldn't have come back better if I had to have breast cancer this was the one to have.  Stage 1 no lymph involvement, Her2 neg and ER PR + .8cm.  All good news, clear margins.  Good health otherwise did alot of immune boosting and alternative along the way.  The problem started with my first dose of radiation therapy yesterday (5 day 2 times a day).  Within 20 minutes of radiation I developed a sore throat and sore mouth.  I told the radiation oncologist about it and said it could not be from radiation.  I had an afternoon treatment and then another one this morning.  Now my lips, tongue, throat and inside of my nose is all feeling burned and I am so stuffed up.  I spoke tot he radiation oncologist again and they said to stop treatment.  Now I am concerned about long term damage and other cancers occurring, head, neck etc.  This just does not seem right.  Has anyone had this happen? What can you do for it.  I am fearful since I know that the chronic affects of damage can be slow coming long after the initial acute problems have healed.  I am going to undergo hyperbaric to try and heal. Any ideas?