I assume you shot an 84 (18 holes) or a 42( 9holes ) on your first round as a Tour pro?
This happens cause when you tier up, you get a "new" average, only scores shot at that tier are counted towads your average. If your first round was a 29 your average would be 58 right now. It will however fluctuate quite a bit for the first few rounds. Once you have shot a good couple of rounds at Tour pro it will settle down and only go up and down by smaller margins. This will happen again when you get to master, TM and finally, legend.
Hope this helps, Good Luck