Thank you for your query.
If the skin is cracking and bleeding even after applying Vaseline then your daughter needs to be seen by a doctor or dermatologist
to know the exact reason for the issues described by you. Without having a look at the lesions it is very difficult for me to hazard a guess. Till you show her to a dermatologist you can continue applying Vaseline.
I hope I have answered your query to your satisfaction.
Wishing your daughter an early recovery.