If an electron turns into a black hole, does it retain its charge? If an electron becomes a black hole, does it retain its charge? Or does it lose it? What if a proton becomes a black hole?
 A: No, it would have to get rid of its charge and much of its angular momentum. 
In the black hole electron reference in Wikipedia, by Alfred Centuari, explains why it's not likely that an electron could be a black hole (BH). Essentially, for its small mass, if it keeps the charge and rotation it becomes a Kerr Newman BH. But unfortunately it would be super-extremal, meaning it would not have a horizon. It'd be a naked singularity, or it would have shed most of its charge (and they don't come in continuous units) and angular momentum (also not continuous). 
Whatever it would then be, it won't be a BH.
We'd have to have a quantum gravity theory to account for what it may be. Only with that could we possibly account for a naked singularity. But then we'd also need to incorporate quantum electrodynamics, because of the charge. So, we're stretto far from thinking it could be a BH. All those arguments above point to no. 
A: From the Minimum mass of a black hole section of the Wikipedia article Micro black hole

In principle, a black hole can have any mass equal to or above the
  Planck mass (about 22 micrograms).

The mass of an electron is about $9.11 \times 10^{-22}$ micrograms which is much less than the minimum black hole mass given above.
However, there are electrically charged black hole solutions such as the Reissner–Nordström metric.
Lastly, there's the Wikipedia article Black hole electron which looks at the speculative idea that the electron itself is some type of black hole.
