Advice? As noted by many others on here, focus on control. Speed will come as you develop more control. Try aiming for endurance by practicing at a certain bpm for 15-30 mins at a time. Increase every two weeks, or after you feel comfortable.
Decrease or increase the time and bpm as necessary. That endurance will help you build control.
stop if it hurts. Endurance will help you buid up control, and speed will naturally follow.