97 toyota 4runner head unit install

you stuffed up  It's alright, it happens to the best of us. LoL

Yes, you have most likely blown a fuse, my guess would be that the illumination wire on the back of the original is shorting out somewhere, does the instrument cluster still light up when you switch the headlights on? If not then it is the Ill. wire remove the head unit, cap off all exposed wires, there will be a couple  most likely. Whilst your there swap the power wires around, you have accidentally connected your Acc. feed to constant and your constant feed to Acc. So when you switch the car off, there is no constant power running to the memory bank of the head unit. Good Luck