Is it safe to get a piercing if you have mrsa?

Yes. As long as you're not piercing an active infection. Practice good hygiene before, during, and after the piercing is important.
Bact. resistant Abs. Lowrisk. Staphylococcus aureus frequently present human skin & respiratory tract, especially nose. Mrsa merely means resistant multiple abs. Control of this bacteria, as with all, a function of immune system. Sa most commonly a commensal bacteria, but that reality not good for marketing fear. Dietary choices, activities, emotions & any internal control affecting staph & immune function can change.