Did I ruin my multimeter with a current measurement?
The current measurement circuit in a multimeter needs to be low impedance. That means it is possible to expose it to overcurrent. Actually it's quite easy: All you need to do is to put it on a voltage source with a little bit of oomph, with nothing to limit the current. 

A very easy mistake to do, as you no doubt know by now.

Because of this, any multimeter worth its salt has a fuse on the current measurement circuit(s).

Since the volt- and ohm meter circuits are separate high impedance circuits, they don't need to be fused, and will likely still work, even if you blow the current fuse(s). 

This means that you can pull the fuse(s) out and measure them with the ohm meter on the same multimeter. A good fuse should have very low resistance, a blown fuse should have infinite.

When replacing the fuse(s), get good quality ones. They should be filled with sand, so that they don't explode if you accidentally short (e.g. try to measure the current across) the mains or other high energy sources. 

Here is a text from Fluke explaining why using quality fuses is important.