Well i dont know a spell but there are natural ways to grow you eyelashes, such as:
Moisturising them( vaseline/ olive oil)
Eating fresh fruits and vegies containing Vitamin A,E and B.
Manage you're stress.
Moisturising you're eyelashes will also prevent them from bristling and falling out, eyelashes are the slowest growing hair on your body so patience is the key :)
Hope this helps
Hmm this got nothing to do with growing eyelashes but does the curlyhair and makeep urge hair grow spells work ?and what about the changing of urge eyecolor like the green eye spell or the redeye spell