Personalty I don't think high (or good) self esteem/self worth is a bad thing because it indicates self respect. If a person is feeling hurt due to sensitivity then it just means they feel things deeply, that's it. So, depending on how or in what spirit the mental health person said to 'lower' the self esteem (it could've been as an attempt at humor, I don't know) then it's really not good advice. It sounds like a kind of lazy attempt at a solution.