RPMs won't go down at any point once I start moving

[februarysnake]

So I recently adjusted my idling screw slightly because my bike was idling very low, (around 800 RPMs) and was sometimes dying as a result. I barely touched it, just enough to get the idling RPMs around 1200. That was last week and it's been riding fine. But today I get on it, give it some throttle (up to around 4000 RPMs) and it just stays there. At stoplights, when I'm slowing, when I'm shifting... it just stays at 3500-4000 RPMs. Very alarming and loud. I kept turning it off at stoplights, restarting it so I could take off at a normal idle, but the problem keeps happening. Any advice?

Edit: I've found some answers with the search feature but I'm not being given an option to delete this post when I click "edit". Sorry.