overcharging

If you were drawing enough current to melt the vr, it is highly likely you fried something else in the circuit. Possibly wiring or the ignition switch. Cooking the ignition switch would cause some of the other issues you are seeing. Depending on how the ampmeter bypass was done, that could have contributed to the melt down. It sounds like the circuit may have been left unfused after the bypass. You should definitely check for fusing before you start driving again.