Going from fuzzy to small is a huge difference. The logical next step from fuzzy is rat pup.
Doesn't mean you can just feed any rat pup some can be much bigger than others, you need to feed something that is equal the girth size (widest part of your BP's body)
Also spitting a prey back out because of the size is not a regurgitation so your snake will be fine and you can resume feeding next week as usual with an APPROPRIATE size prey.