There are those in favour of belts and those against.
I have never really understood the against sides point of view although they commonly say the belt can become a crutch. No idea what that means in the scheme of things because if belts are allowed in competition then how can training with one be a crutch?
What most powerlifters do is warm up without one until you start getting up to your work sets then put the belt on.
Will the belt stop you from hurting your back? In your case maybe not but then again it may have.
You see if you are just starting out as a lifter then you really shouldn't be squatting in sets of 10. I would recommend sticking to sets of 5 or less until you have the technique down and get it right every time.
One of the critical parts of the squat is the set up itself. You must get the setup right before you even begin to descend. You will often hear lifters talking about getting tight or staying tight. This is in reference to their core. You must keep your back arched chest out and core tight and hard as a rock. This is what the belt is for. Just putting on a belt wont do much if you don't know how to use it.
You need to take in a huge breath of air into your belly, not your chest. Then you push your belly out into the belt. Then you squat and release air once you complete the lift. This is how you stay tight. Sounds like a lot to remember and it take practice but after you do it again and again you get really good at it.
Now if you do sets of 10 it's going to be really hard to stay tight and this is where form issues like the one you had come into play. The most common error in squatting is leaning too far forward and losing the back arch. This is where a lot of back injuries will come from. However with good form squatting IMO is safe for the back.
This is the same reason why it's not recommended to do high sets of deadlifts.