I'm At A Loss

[Lord Sorril]

That can cause a problem 1.5 months afterwards? Wouldn't it have become a problem immediately?

Digestive juices can irritate the lining of the lungs and allow an infection to set in.

It is very possible that the true issue was prior to the regurgitation and remains unknown.

Either way you should see a Vet if the snake is continuing to deteriorate.