Just to make sure we are talking about the same stuff here.
You are turning the weight locking screws first right? The ones on the side of the riser. There are four total, two on the top limb pocket and two on the bottom. Unless you have an older Hoyt hunting bow with only one side weight locking screws. They are the same size allen wrench that the limb bolts are.
I fear you may have loosened the pivot point screws. They are at the back of the riser and connect the pocket to the riser. They use a smaller size allen head, and are connected. They have to be torqued to a certain weight and should NOT be played with. If you think you undid those, bring it to a shop as they will know what to torque it back up to. DONT shoot it without them being checked first though, as you could do serious damage. Hopefully you didnt strip them, (unfortunately its not hard to do).
After you have loosened the weight locking screws, you may turn the limb bolt counter clockwise to lower the poundage. 5 turns should equal about a 10 pound drop in draw weight, but not every bow setup is the same so check it with a bow-scale. Also, make sure to turn the limb bolts equally, top and bottom. As this will keep your tiller the same.
To be perfectly honest, you can change the draw weight without loosening the weight lock screws, it will be harder to do, but Ive been a dunder head and forgotten to undo them once or twice and they honestly dont do all that much. I think if Hoyt "ridged" them, it would serve a much better purpose.
My bet is that you undid the pocket to riser connection and that you need to get it torqued back up at the shop. If you are still unclear on what screws are what, have them go over it with you.
Good luck, hope all is well with the bow.---Matt