I've never done that many dives daily and for days, but I would think there is more of a likelihood of getting swimmer's ear or worse. As someone asked, have you had it or worse before? Anyway, I do this:
1. Wear a hood (swim cap if tropics, brought down over ears) or Doc's Pro Plugs. These 3 things prevent water from going far into the ear. Some will still get in.
2. Don't do any quick sideways turns and be careful to keep head straight (if possible) if donning/doffing fins in water. Don't fool around swimming upside down, etc.
3. Use Q tips after each dive (many disagree--no problems for me for like 50 years of swimming, etc.).
4. If water gets in that you can't "jerk" out, use ear drops. I use standard ones bought at LDS--clears it up in a very short time.
I am prone to Swimmer's Ear or worse. Haven't had it now for years.