I'd like some more info ...
CIAK is absolutely right, ice will reduce swelling and underskin bleeding (and, therefore, bruises).
Systemic zinc (taken as a tablet, for example) will speed healing of cuts. Make sure she eats well and drinks plenty of water.
But, what exactly are you doing that is raising the marks? Are you talking about bruises, broken blood vessels (large red marks), cuts? Are you using toys and if so, which ones? Are you starting with warm-ups or just jumping in to heavy play?
There are plenty of really good websites (start with
Sexuality.org/BDSM , books ("The Bottoming Book" is a wonderful starter, local workshops, and large number of social/educational groups dedicated to BDSM and safe play in Toronto. Start looking for courses at
Good For Her and check out the
NOW Love & Sex Guide
DSSG Toronto is a great local resource - check the links page. And
Northbound Leather will also be able to direct you to events/club nights around the city.