Yes, they CAN do damage to their faces if this continues...they can end up with an abscessed mouth that requires surgery, not to mention broken embedded
teeth, etc. So you want to minimize this...maybe locate the enclosure in a quieter place (so you aren't walking past?) or cover the cage (or use a room divider
folding screen) to block his view. (which defeats your easily observing your pet, unfortunately...) The BCI I had was quite food motivated but wasn't inclined
to hit the glass when it wasn't feeding time, & even so, it rarely happened. Maybe you need to avoid walking so close to his cage, & pay close attention if you do?
One way to quickly "change the channel" on an overly-food-driven snake is a quick spray of water to their face...it doesn't hurt them, just startles them & is a
complete let-down as it's nothing like prey. You might be able (translation: if I had your snake, I'd be inclined to try this) to "teach" him to back off & wait for
a more positive prey identification if you rigged up a little sprayer of water, with tubing so you could spray it when further away...as when you see he's tracking
your motion thru the glass & is in danger of striking the glass. Because one thing is certain: your boa's food drive will only increase, as will the force of his strike.
Boas are not shy like BPs, & I don't think you'll dissuade him from eating...you just want to slow him down, teach him not to chase every motion so much.