blown fuse for instrument cluster.

I started my car a few weeks ago, this is on my c280, and my instrument panel was blank. Nothing would move or work, none of the gauges or lights. But the the temperature gauge still worked... anyways, i took it over to my mechanic (not a mercedes dealer) to have have a look at it. it was only a blown fuse. He put in a new one and the gauges worked and the miles were back on. but the miles hadn't registered during my drive to the mechanic (i know becuase i have a log book for driving miles that is a tax write off through my business). My mechanic told me that it seemed ok, but the computer in my car might have registered that the miles went haywire. He said that i should have it looked at by my mercedes dealer just to be safe! should i have it looked at? or is it no problem? Everything works and the miles are fine, but it didn't register the 20 miles to work. is that ok? or does the computer know TMU, True Mileage Unknown?
Thank you everyone...

Sincerely,
Petra