Boa rubbing nose on glass

Hello

So my 7yr old male BCI has recently (past two weeks) been rubbing his nose on the plexiglass of his Boamaster cage (4x2x1). I didn't think anything of it at first, but now he has a bump on his nose which leads me to think that this happened because he's been rubbing it on the glass so often. Examining him, he has no symptoms of an RI or anything like that, his breathing his normal, head at a level position etc, but based off what I have read, this can either just be a phase or require a visit to the vet. I'm going to thoroughly check the temps tonight, but I am confused as to why out of nowhere this is happening. I can only think of a couple things:

-too big for his cage: this boa is about 6 1/2-7feet, so it may be time for an upgrade. He hasn't grown that much though and he's never made a big deal about it until recently.
-he's housed underneath a female boa. I highly doubt this is the issue unless this is the "time of the year" where he wants a lil somethin' somethin', and she's fairly new (got her in January) so i don't know if he can sense something from her and it took all this time for him to notice.

Otherwise he's pretty healthy; feeds every three weeks, defecates normally, no sign of RI as mentioned.

Any thoughts?
Thanks!

Could be because of the female or something is off in the cage (double check the heating, did it get too hot?). And it IS that time of year for pairing up boas, so your female may be throwing some pheromones that are driving him crazy.
If everything on the husbandry front is good, you may want to try covering most or all of the front of the cage (drape a sheet over it or tape up some paper) and see if that calms him down from rubbing?
Some boas love to rub and usually a change of caging may solve it or removing his ability to see 'out' may solve it. He should be fine in that size cage.

Depending on how bad it gets, it can cause infections if he rubs raw, one of mine was in a tub and rubbed so bad in high humidity it caused the infection to get into this tooth and that required vet surgery. Moved him to drawers style freedom breeder and he was fine. I had another in a glass cage with screen top and no matter how perfect it was, he constantly rubbed the screen, so moved him to a plexi cage and he was fine (although he does start rubbing around this time of year again grrr).
A lot of times if they rub badly, the bumpy nose look will never go away (call it a 'rhino' nose).