Mistakes like this can be very expensive, so doing such repairs yourself
to save money is not a good decision.

I suspect you shorted a hot wire to the window regulator by touching it
to the door which is the car's electrical ground. The window regulators
are controlled by relays which are probably located in the black box
with the car's electrical fuses. The best case would be that a relay was
burned up, the worst case that the wire itself was damaged and now needs
to be replaced.

But your message header is that the car's fan is not working.
What does the fan have to do with the window regulator?

Suggest you take the car to an independent M-B shop and ask them to fix it.