I am so sorry that you are going through this. You must be frantic, I know I would be.
Did the problems start after the fast or since you started with the 10 lemons per day? Have you been able to eat anything else besides the lemons? Could this possibly be a breaking down of weak enamel in order to make way for new enamel? (not sure if it would work that way, just thought I would ask).
I hope you are feeling better and able to eat normally again real soon. Maybe a coffee enema or a colonic might help?
Now I am back on the fence about fasting since you've mentioned these problems occuring.