There is a possibility of breaking out depending upon what acne treatment you are switched to. Some treatments make acute outbreaks occur when first applied even the best most reputable treatments can do this. Some treatments will be harsh and irritating to your skin and will cause this problem by the nature of their vehicle. This does not mean that new treatments are ineffective but rather means you may have to expect an initial worsening or gradually titrate the new treatment to your skins' tolerability (i.e. start slowly..every other day) rather than daily.
Either way discuss with your dermatologist.