Just checking as well - are you sure it's a cracked nipple?
If you haven't had issues before with this pain, watch out for shooting pains in between feeds etc. this could indicate thrush. I know when I had thrush the pain at first attachment was excruciating.
If so, you can have thrush in your nipple before it is visible in bubs mouth.
Use the daktarin oral gel on your nipple instead of canestan cream. It does the same job, but you don't need to wash off, and bub will get a but when feeding from you too.