Sleep Sack and Rolling Baby

My boy has been trying to roll over completely for weeks now and he finally did today. He is 4 months old.

We still use a sleep sack at night-- should I try getting rid of that? It took him a while to be okay without swaddling so this worries me a tiny bit.

However, most of the time he will lift his head up when he is on his belly. Sometimes he would turn his head on this side but there has been times that he will just bury his whole face and not move. I was so looking forward to him rolling but no I'm too scared that he rolls on his sleep and can't breathe right 🙊🙊

What would your suggestion be?

Ps.. this is the sleep sack we are using.