For "reason", you usually want to use *:TEXT instead of 1:TEXT

You don't need the ! prefix in :TEXT: event which targets a channel, because your own messages in a #channel never trigger the :TEXT: event.

It does set a cooldown that affects everyone. As shown in the link I gave above, you can have a separate cooldown per nick and another cooldown for the channel as a whole.

It's a good idea to have variables which are unlikely to be trampled on by other scripts. If this is just for #mychan, then name the variable %comwait.#mychan

If I were to do this, I'd also use a variable name which didn't look like it was being used in a $com, $comcall, or a sock* event. %cooldown.#mchan would probably be better for when you look at this script for the first time in 6 months.

Unless you have an alias named "Hey", that will be an invalid command that gets sent to the server to see if it recognizes HEY either.