It is okay for the drains to get a little wet but try to keep it to a minimum. The drain itself can act like a wick drawing in water. Once you are done pat the area dry and re-apply the dressing.
I would cover the sites with a tagaderm then take a string (shoe string) and wear it like a necklace attaching the bulbs to the string to secure them so you have use of both hands while showering.