Greetings. This head ache that you had yesterday may not be related to FUE at all. Sun exposure - that too in this hot summer can trigger a migraine like head ache and therefore - you had head ache / vomiting / nausea - etc. Drink adequate fluids. Avoid sun exposure between 10 and 4 pm. Use a cap at all times during sun exposure and follow all other means of hair care that may have been advised by your hair transplant surgeon post surgery. Hope this helps. Warm regards, Dr Govind Suresh Mittal, Bengaluru.