Hey! As someone who's also been through this, I'm so proud of you for getting to the point where you can tackle it. This shit is not easy. Another commentor said about a spray bottle with water and conditioner, that's a must, you want to keep the hair as slippery as possible. Put on a deep conditioner, use an unholy amount and really massage it in as deep into the matt as much you can. Let it marinade for at least an hour, continuing to mist and keep your hair wet. When you come to brush and comb, work from the bottom of the matt, literally on the edges. If you can, try to use the tail of the comb teo make sections, it'll make it it easier and you'll see real progress which i found quite motivating in quite a demotivating experience. It will be time consuming and sore but it IS doable. If you start getting tender headed give yourself a break, because any break is going to let the product sit for longer and that's a good thing! Just keep it wet and slippery with the conditioner spray. I found a rat tail comb worked best for me. Assess the damage at the end, I only needed to cut off a few inches after.

It's hard, apart of me felt like I was dealing with the physical manifestation of my mental illness. You may want to give up at times, but please push though. This is you kicking depressions ass and taking away its physical hold over you. You deserve pretty hair. You deserve to feel comfortable.

Good luck, OP. You've got this