i think its a coincidence that the radio died after doing that…inline fuses really are worthless to speakers, but it wouldnt have caused your problems with the headunit itself.
i would say recheck every power wire and fuse to make sure all is well, including the fuses on the back side of the headunit, if your has any, and go from there. get at the wiring with a test light to make sure there is not problems with it.
Do you have another headunit that you could try and wire in there quickly? this could allow you to narrow it down to the unit for sure.
goodluck