I am not an ophthalmologist however am a dentist. I too have had a chelasion removed. It’s possible that the headaches are caused by the procedure, because what they do is, create a tiny cut in the eyelid and scoop out the goop. ( said to be ‘marsupialised’) so depending on how nicely or not your lesion was ‘marsupialised’ , could mean more scraping and what not. It’s the procedure probably and not the anaesthetic, which is a few drops infiltrated superficially, not a nerve block. Give it a few days, paracetamol, and you should be right as rain.