I really need some advice about blowjobs!!

[Jaclyn]

So I gave my boyfriend a blowjob for the first time a couple of days ago. This was the first blowjob I've ever given. At first I didn't know what I was doing, but after a few minutes, I caught on fast and really got into it.
I can't believe I'm saying this, but I actually did enjoy doing it! I liked the taste and how it felt in my mouth....that is, until my jaw started hurting like crazy!
I wanted to make him cum, but I couldn't finish him off because of my jaw! He said he wasn't mad and he didn't want me to be uncomfortable, and I know this is true because he didn't act mad or anything. I can't help but feel a little bad, though.

Okay, so what I'm asking is, how can I prevent this serious jaw pain? Do I just fight it and keep going? And once he cums, do I let him do it on my face or do I try and swallow it all?
Please don't laugh at me, I could really use some advice here. Guys and girls, let me know what you think.
Thanks!