Talk to General Physician on Throat Problem After Radiotherapy

Assalam o alaikum. Can you plz request any oncologist to help? My mother's having severe pain in her throat and it started during her radiotherapy, first we thought it's sore throat but her oncologist indicated that during the therapy some radiations might have done this and it will be okey after few days. But she's in extreme pain and can't eat or drink properly. Is there any thing we can do to cure it?? Please help cuz her doctor didn't guide us at all in this matter. And i also want to mention that her radiotherapy has been completed on 2nd of December.