As long as the prey item is less than 1.5 times the size of the snake's widest point, it should be okay. Just give him one
Do the fuzzies still leave a visible lump?
The best way to do it is to get a good digital gram scale and weigh both the snake and the food items every feeding day. Then you can go by something like the "Munson Plan", which can be found all over this forum with a search.
Another thing to check when a snake refuses to eat is to make sure the temperatures are correct, plenty of clean water, etc. 75 degree or so cool side and 80-85 warm side, measured with a good digital thermometer with a probe, the probe stuck to the warmest spot to get the hot side. (on the glass where the UTH is stuck if you are using a UTH)