I'm trying to grow long hair...i need advise please?

I am a male. My hair is straight overall and is very thick, yet very fine. I currently have a mullet. I have a mullet because i am one of the few people who actually look good having one (I get good comments all the time) and it looks good on my face. However, i have a problem i need advise on as i have never grew my hair this long before. Even though my hair overall is straight, it tends to curl up at the very ends in the back and there appears to be a "dent" in my hair on the back about midway. What should i do about this? What is happening? I wash my hair with hot water and use conditioner...Anyway, i would greatly appreciate any advise/tips on this as i have never grown my hair out before. Thank you.

I'm trying to grow long hair...i need advise please?

It sounds just like you need a bit of a trim. Your ends are probably curling up since they are growing out. It's best to trim about every 8 weeks. Your hair will still get really long! Also, the line can be from your neck. It might be ok for the first hour or so, but once it totally dries, then line shows up.

The flip can also be cause if your hair is just at, or just past your shoulders. It's now used to laying there, so it tends to want to curl. You can make that go away (and you might hate this idea) but flat ironing it. I would try a good trim, first. Have them cut it all to EXACTLY the same length (not undercut) and it will lay under, and not tend to flip-out.