I have never heard anything about Lucid Dreaming being damaging but i must say...im embarassed to not know what derealisation is....

but I guess it has something to do with your perception of what's real and what isnt?

the practice of reality checking surely would help this? to stabilise the fact that what you are experiencing is real. (im guessing youve read up about what reality checking is!)

maybe someone else has anything to add