You only need to do a Canadian medical when you want to go back to Canada to fly. If you do that and you end up working for a commercial company, as soon as you do your PPC your licence will be reactivated.
WHAT YOU DO NEED TO DO NOW IS, go to
http://www.tc.gc.ca/media/documents/...0811-02_bo.pdf
fill out the form and send it in, as the old paper license is no longer valid.