Help! Sleeping against crib

So my baby will be 4 months next week and has been sleeping in a doc a tot in his bassinet since he was born. He didn’t like to be swaddled so we thought this was a good alternate. This was great as he always slept through the night but I believe was a mistake on my end. He started rolling over last weekend so we took away the doc a tot and put him in his crib. He sleeps through the night (moves a ton) however he instantly rolls to his stomach the second we put him in the crib and scoots himself to the edge of the crib so his head and entire body are up against the bars (We have a breathable mesh bumper). Mind you remember he is face down so I am not sleeping because I’m too concentrated on the monitor to make sure he is ok. I have the owlet as well for reassurance but this isn’t a good sleep habit to get him into. Any suggestions on how to keep my baby in the middle of the crib away from the bars?? Thanks for your input.