Does the Arduino deteriorate after shorting the voltage regulator?
Of course, if you can upload the code, you can continue to use it ;)

Even if the Arduino is cheap, it is really reliable. There are always some short circuit protections.

The Voltage Regulator (I think it is a simple LM1117) has a overcurrent protection too (see: http://www.ti.com/lit/ds/symlink/lm1117.pdf)

So, don't worry. You can continue, continue and continue to use it...

Edit: just a note: never drain more than 50mA on an output. This will destroy the pin on your Arduino.