Ankle sprain - plaster. They are needed?

I got an ankle injury 3 weeks back while playing badminton. I was diagnosed with an acute ankle sprain and a twisting injury. They put one of those lightweight plasters (pakka). It's been 3 weeks since. I'm at a different location so I consulted a different doctor and they suggested that plaster should stay for 6 weeks in his opinion although there is no injury to the bone. But in any case not extending that long he said we will wait 4 more days then cut it. He also wrote me tests for Vitamin and urea (full body). Which I'm not sure if they are needed? I consulted over the original doctor over the phone and he said there is no need to extend and we can get it removed in a couple of days ,if there is no pain (which there isn't any and I'm able to walk just fine with plaster on). Seeking more advice on this.