What to do?

yeah he sounds like a player, I would not talk to him again, even if he messages you
Nudes are something special- you're showing your body- so a guy should have put effort in before you send them
Don't trust guys that easily, definitely give it time next time before sending anything or things like this will happen

Also think about why he is your crush, do you like his actions? or is he your crush just because of looks?
What has he done for you to actually have a crush on him?
Being hot isn't something guys do for anyone specifically, it has to be some actions

I like him because he's really funny. It just hurts that he NEVER wants to get to know me. I've asked him out and he said,"Hell no!" The next day he asked me for nudes. Honestly idk why it also hurts because it's like he doesn't want nudes on me because he found somebody else. He is very trustworthy but the thing is he's just using me. I've knewn him since about the end of last August. He would always ask me for pictures and ****. It always felt like I can trust him with my pictures and I had a sense of validation. I felt like I could trust him and I felt a bond between us even though he doesn't like me. He really does do this sometimes and goes weeks without talking to me. I have no idea but he won't awnser me. I told him,"So you used me?" and he left me on read.

What gave you the impression he is trustworthy?
Thing is a lot of guys are funny, but it only matters what he does especially for you.

He obviously finds you attractive as he wanted your nudes. He doesn't want to get to know you because he got what he wanted- nudes, so why put that extra effort in? If you said something like, before I send you anything I think we should get to know each other more then that would've worked! He would've either put that extra effort in, or he would've not bothered and you would've then known how he would treat you.

With the leaving on read, it's honestly because he can't be bothered. Loads of guys do this. Imagine you were a guy and you got what you wanted and you thought it was ok because the girl agreed to send you the nudes. Then the girl starts saying it's not ok and that it's using her. Can you see the problem there? This should have been not ok at the start.

With the someone else, I mean yes guys can talk to multiple girls at once. You guys aren't exclusive so he has the right to talk to someone else.

It's unlikely to work with this guy unless you leave it there and give it time. He might come back and next time make sure you let him know that he needs to put more effort in and get to know you before you send anything! He needs to deserve you!
Don't worry about it too much- guys come and go, you never know, you can meet someone tomorrow! Focus on yourself for now and leave the work to the guys

Well the thing that made me like him is the way he compliments my body.

Ok so you know there is definitely physical attraction. He will probably be back to ask you again at some point, but next time just let him know you need more effort- like getting to know each other/ going on dates/ seeing actions to show you he cares about you and maybe being exclusive before you send anything revealing again. The more effort he invests in you the less likely it is he will ignore you in the future and he is also less likely to invest that effort in other girls! Guys may talk to a lot of girls but they won't be working hard and putting all that effort in for everyone!
I would probably act like it didn't bother you much at the moment and it was just a bit of fun for you and if he comes back just start off with letting him know your standards Don't be scared to reject him in some things too- guys like challenges. By arguing now, all he can do is probably reassure you he didn't use you if he bothers to do that, but that's it at this stage. Just have to give it some time.

Well the thing that made me like him is the way he compliments my body.

So he has said nothing about your personality? That is not, as someone else suggested, a physical attraction; he is just pushing your buttons to get nudes.

Okay thank u! I appreciate you for giving me advice! I wish you could PM me for further more advice but we're both on anonymous :/

That is shocking advice. You are happy to hear it because it validates you thinking this guy likes you and you were right about him. There is no attraction. He just wants nudes, not a relationship.

He is only looking for your body gal. Maybe is not interested in you in the slightest. Maybe he just to have sex.
But I am sure you deserve better than this. Please try to move on.
Or do you like him?