Congratulations on finding a good alternative for their pain medications. Its always best to withdraw from that pain medications under a doctor's care. If you can't do that for some reason the The National Pain Foundation suggests that reducing your medication 25% every other day should prevent symptoms of withdrawal. If they should crop up simply go back to the last comfortable level of drugs you are taking, and taper off every third or fourth day (or whatever works). 

They also suggest that you drink lots of fluid, try and stay calm, try to focus on other matters and reassure yourself that, this too will pass, as it will - the withdrawl symptoms will cease over time. Good luck!