What should I do when my hair feels dry and frizzy?

My hair wasn't like this before... T_T

At some point, the flowing, silky feeling disappeared, and

It felt a bit dry and crumbly.

For reference, I have long, straight hair and I tend not to get any treatments done. Just dyeing, perming, using a curling iron, and blow-drying.

I wonder if it turned out this way because I've been twisting my hair into a bun at home all the time for the past few years...

I wonder if it's because I haven't been taking care of it enough, and every time I look at my hair, it makes me a bit sad to see how much it has changed over the past few years.

It used to sway even without doing anything...

Usually, I just shampoo, conditioner, and apply hair essence.

What can I do to make my hair come alive and bouncy?

🥹

I have absolutely no idea about self-care methods like this, so I would be really grateful if you could share some great tips!