One's used to Count Dracula ripping layers off and biting through bits of muscle (6)
I believe the answer is:
abacus
'one's used to count' is the definition.
(an abacus is used for counting)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for abacus that I've seen before include "An old counting frame with beads" , "Counting device" , "Basic calculator makes" , "Old counting-frame" , "As a cub (anag)" .)