So i've been working on a paticular part of a song my bad is in the process of writing. It's set at 200 bpm, and I've just gotten that paticular part up to 170. My progress on it has been going quite well for the past couple week, so I figured that I could take a day off from it. The next two days after that I was too busy to practice, so it ended up being three days in a row that i didn't practice it. My whole afternoon today was free though, so I decided to spend a lot of time working on it. I soon found out that I kept making mistakes. I decided to slow the BPM down to 160, but I still wasn't able to play it cleanly all the time. I took it down to 150, and I still made mistakes.

The thing is, they weren't consistent mistakes. They were all completely random, so there wasn't one specific thing I could concentrate on. Now, don't get me wrong, I wasn't messing up all the time. I was playing it perfectly about 50%-70% of the time, compared to a few days ago whre I could play it perfectly 90%-100% of the time. Still though, I want to have it perfect, not almost perfect.

So what should I do? It took me a while to get it to this speed, and I really don't want to have to start over, especially considering I was doing it fine a few days ago. I was thinking of just practicing other stuff for a day or two, but I don't know. Anyone have any thoughts?

Sorry for all the text.
i find that if you forget about it for a day or two it helps, but that obviously didnt help you so, its really all up to you
Don't worry about it! Your progress is not lost. You just had a day where your concentration wasn't the best.

Hit it again tomorrow.

Take the tempo right down to a speed where you can play it 100% correct, 100% of the time, even if this speed is 60 bpm, the important thing is to get your fingers moving in the correct way all of the time - building the muscle memory.
Slowly build up the speed by small increments, not continuing to a faster speed until you have it 100% correct, 100% of the time.

That's what I was doing, though. I was playing it perfectly just about every time. I did mess up every now and then, but that is unavoidable.

Don't worry about it! Your progress is not lost. You just had a day where your concentration wasn't the best.

I hope you're right.