Tips for damaged hair?! PLEASE HELP

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My hair is shoulder length so I can't cut it. Just the top layer is super damaged, everything underneath is silky smooth.

I need suggestions on products! I must blow dry it for any volume and I LOVE to curl it so I can't stay away from that lol

I get regular cuts and I've only colored it once in my life, and just a few highlights. I use heat protectant and oil everyday.

I can't really figure out how it keeps getting damaged even after I cut it...and why it's just the top layer.

Any advice welcome!