Plenty of people use IMR in unregulated mods successfully but they do so at risk. If you want to be safe you have options. Regardless of what you choose to do, you'll need to replace the hot spring in your SB. Those work well. Without it that battery would have likely exploded and not only ruined your device, but could have been a serious fire hazard.
in other words, without the hot spring, don't put your 18650 PV in your pants front pockets! <G> (1) You can buy and use a
Kick. You will need to use shorter batteries but the Kick gives you wattage control and has built in short circuit protection. They are made to be used with IMR batteries. (2) Buy and use the
Vape Safe. It is a reusable fuse. Its sole purpose is to protect against battery shorts and will likely save your device, batteries, and spring. (3) I lieu of the previous suggestions, if all you do is replace the hot spring, invest in protected batteries which will shut down in case of failure.