Well first off, welcome to BP.net
What you are feeling isn't anything to worry about. Your Bp isn't trying to constrict you... They only do that after they strike. What you are feeling is the BP holding on to you (he probably thought that he was slipping so he "grabbed" on tighter) In no way was he trying to do you any harm.
Many people (including myself) feel that a snake has no business anywhere near anybodies face. Not because they are dangerous, but and you seem to agree... we don't want to get bit in the face lol. I think that what you are feeling is very normal. you need some time to get use to your new snake just like he does with you.
Basically you just need to take a deep breath, and remember that a BP is harmless. Even an adults bite really isn't that bad. But with any animal you must respect them and treat them with care.
To be comfortable with your snake you might have to take some steps to keep him in check. If that means actively keeping him away from your neck/face then that is what you need to do. The more you handle your BP the more comfortable both you and your BP will be with each other.