I agree with all that has been said. Beautiful boa and I would not be concerned at the moment.
See if it gets worse and make sure temps and humidity are good.
If sheds have been good, humidity should be as well, but boas can handle pretty high humidity. Make sure you at least 60%+ for a bit and that could help IF it is a skin issue.
Overall, BI's are vey hardy when good husbandry is practiced. Good to be careful/cautious, but I would not get too worried yet.
Good luck and keep us posted!