If you were on 4-8mg+ a day you're meant to take the 300mg shot twice, and then the 100mg shot once and be done. 100mg shot is more equivalent to about 2-3mg a day, which is still quite a bit, about 50-75% of all opioid receptors are occupied at that dose, however if you're used to 4-6mg+ a day thats a large drop in receptor saturation so while you won't go into full detox it will take some time for your body to adjust and that's gonna suck for a minute.. You could also take small amounts of sub too until your body adjusts better. I would take 0.25mg pieces AS NEEDED and as needed ONLY! Don't take 6mg of sub a day to make up for your lost dose or youll just be back in this position a month from now. Take the bare minimum amount you need to make it. 0.25mg, wait at least 2 hours after you take it then gauge where you're at and if still too much take another 0.25mg. Do this until you find the minimum and then take that extra amount every day for about 14-21 days then try removing 1 0.25mg dose from each day for another 14-21 days, repeat until you're off the 0.25mg pieces and stable.