No your not stuck on beta forever, your just testing it before stables comes out, but its always important to back up your data as beta could break your phone and your data would be lost
We always notify to Beta participants to backup the data before updating to the Beta OS, as you cannot restore your data once you update your software. Howver, if you still wish to rollback to previous OS, you can call 1-800-726-7864 and request the location to the nearest Service Center.
