Did you get it out? Fingers crossed it makes it!
Every situation is different, it is so hard to tell exactly what is going on remotely. I think the general rule is to go very slowly with assists - they can take hours or even longer. If during an assist you are concerned you are moving too quickly, I would give the chick a chance to rest up, and that also gives it a chance to finish hatching on its own. You may not necessarily need to see the belly to know if it is still absorbing yolk - can you see its beak? If it is making chewing motions it is still absorbing.
I feel like a big part of assisting is experience - the more times you do it, the more you will be able to trust your gut and make the right choices. Not saying everyone should go out and assist every hatch, just that the more you /have/ to do it, the easier it will be in the future.