Look into loperamide to maintain until ur next script as well in the mean time. You can buy 400 pills (800mg) for like 10 bucks on amazon, it's legal, And I swear to you it is a godlike maintenance drug. What's ur usual oxy dose? I find afte a bender 30mg of loperamide holds me over for 8 hours and u don't feel any high whatsoever but the withdrawals are 90% gone. Then drop ur dose 1mg each redose to taper off.
U don't want to be always on loperamide for long periods of time each time ur script runs out early tho. It will increase ur general opiate tolerance, that's why I recommend a rapid taper of 1-2mg each dose, but it does truly make withdrawals much more manageable.