My bf wants to go down on me but I’m worried it going to put my health at risk.

Im 17 and I’ve been with my boyfriend for 9 months now but have known each other for three years. He knows like my history of bad periods and knows that I’ve been waiting for a proper diagnosis of endometriosis or something since like before I met him. I’ve had bad periods that make me throw up and yada yada yada. But like becoming sexually active has always been discouraged. And I haven’t thought about it until recently. I’ve been referred to a specialist to deal with many of the issues I have with my reproductive system but I can’t get in for another couple of months. Does anybody know if my boyfriend eating me out would cause more complications by becoming sexually active? Or just any advice to those who were reluctant due to medical factors instead of like insecurity or like shame or whatever?