Mouth sores after Master Cleanse

I did a 10 day master cleanse and on the 10th day noticed some minor sores (cankers I think) in my mouth and they progressively got worse over the course of the ease out, especially with the orange juice for 2 days which of course was extremely painful to drink. Im now on my first day of regular eating and find it hard to chew and swallow anything.

Anyone ever experience this or know why they would suddenly appear after 9 days of cleansing? Every once in a while I get a canker but nothing like this. There are a few on the inside of my cheeks and LOTS on the back of my tongue (or so it feels, my tongue is too sore to stretch out so I can see that far back)

Any suggestions would be welcome!

Thanx!