How risky is it to get fat injected directly back to buccal space due to inner mucus and bacteria?

I got buccal fat removal and I regret it. I have been exploring the option with surgeons to get fat injected back to buccal space versus a superficial fat graft. Does the likelihood of developing problematic necrosis increase when you inject back to buccal space (though the inner corner of mouth) versus a superficial fat graft? My understanding is that you are breaking through inner mucus which bacteria can infiltrate. How can I reduce my chances of getting necrosis that can cause deformity?