Water mark- dulled finish

I have "granite" countertop in my bathroom which was installed in my house before I moved in.  I don't know what type it is, but it is light in color- similar to sand.  Some time ago, my roommate left a frozen bag of fruit on the counter overnight which has damaged the counter top.  In the area where the bag was left, the countertop is quite dull with no sheen to it.  The damage is fairly obvious and I would like to have it fixed.  Does this have to be done by a professional or is there a home solution that you can recommend?  Further, the area where the soap was by the sink has turned a bit gray and has small holes in it (unrelated to the water mark, but still water damaged).  I have a professional grade buffer at my disposal, I just need the cleaner, if that's what is required.

Thanks in advance for your help!