If you buy a pair of shoes or makeup and choose the option to pay later, it could show up on your credit report.Affirm, one of the largest “buy now, pay later” lenders, on Tuesday will begin furnishing all new loans to Experian, similar to how a mortgage or car loan shows up on your credit report.So far, the change to this fast-growing form of consumer debt only applies to Affirm loans and Experian credit reports. But other lenders and credit bureaus may soon follow suit.