Blowjob Tips ???

So my boyfriend really loves getting blowjobs, and I love giving them. Except I have some pretty bad problems with my jaw, so it's really hard for me to give a blowjob for a long time. After a while it just hurts me. 
Do y'all have any tips on how to make me be ~better~ at them so I can still get him off but cause minimal pain to myself? I always feel bad getting him started then having to stop. 
Just any kind of advice would be great! He was the first guy I'd ever given a blowjob to (and I was the first girl he received one from 😄) so neither of us really have much experience with it. 
(We both) Thank you in advance!