Which part of this treatment is causing the healing for tendenitis?

I have been diagnosed with tendenitis in the shoulders. My doc said if it doesn’t get better, I will need physical therapy, but for now we are treating it with an anti-inflammatory and a muscle rub with that blue gunk 3 times a day.

They seem to be getting better.

Here are my questions (regarding the muscle-rub.)
Is the rubbing the part that helps, or the blue gunk? I mean, if I rub longer, will I get more benefit?

Or: Does it only help lessen the pain and the real treatment is the anti-inflammatory and time?

What I’m trying to get at is: If I spend more time doing each shoulder, will I get better more quickly?