It seems the OP is new at Arduino and does not have a electrical background. Is the goal of this forum to provide some useful help or recount old issues?
@janmar
Touching 5V is not inherently dangerous.
However it is a good thing to verify the source of the 5V is via a power supply that has some safety approval like CE or UL etc. This will verify the power supply is not connecting you to the mains voltage.
Unsafe power supplies are not unheard of but are not that common.