A few things/questions/suggestions...

1. "if ($nick == $me) { halt }" is useless, because the bot wouldn't be able to activate the event itself anyways.

2. You can just set %lol as a local variable, so that you don't have to unset it every time the script is run.*

3. Why go through the trouble of adding a comma between the channels (without spaces between the channels and the commas), only to replace the comma with a space immediately after? var %lol = %lol $comchan($nick,%x) seems much easier.*

4. Is this script intentionally made to only list the channels that both the nick triggering the event and the bot is in? (as opposed to actually listing all of the channels the bot is in...) Just wondering...

*These are unless you're actually using the variable %lol in that format for some other event.

For fun, $regsubex method:

on *:TEXT:!chanlist:#: msg # Im in: $regsubex($str(.,$comchan($nick,0)),/./g,$comchan($nick,\n) $chr(32))

( five edits later... o_o )