I'm going to assume for this answer that you're on coumadin/warfarin.   It's very safe to use a filler like Juvederm or Restylane while you are on coumadin BUT you will very likely bruise.  How much?  It's hard to say exactly because it depends somewhat on how gentle your doctor is when he/she injects and how actively they use pressure and ice right away to limit the bruising.  Also, many of the "numbing" creams used for 20-30 minutes prior to injecting help because they also constrict the blood vessels a little. 

 As long as you are prepared for some bruising for a week or so afterwards, you probably will be happy!   Dr. I