Once i've been diagnosed with mrsa, will i always have it?

Possibly: Most humans are colonized with Staphylococcus aureus. MRSA is just one strain of this organism. It is possible to rid yourself of the carrier state, but it will take time and effort, using a combination of mupirocin ointment in the nares and continued washing of skin with soap containing chlorhexidine which produces a thin layer on the skin. Rectal colonization is more difficult to eradicate.