You can use
if (/* !iswm $1) msg $chan message with annoying colors
or
if ($left($1,1) != /) msg $chan message with annoying colors
You may find you want to check whether $ctrlenter is $true or $false to see whether your input was normal or was due to using Control+Enter.
You'll quickly find that everyone else is annoyed because you're overriding the colors *they* want to see. If you want to change the way you see the message without actually sending the color code for everyone else to see, you can echo the text to yourself the way you want to see it but use the "." prefix to hide the display from a /command.
if ((/* !iswm $1) && ($ctrlenter == $false)) {
.msg $chan $1-
echo -t $chan $+(<,$nick($chan,$me).pnick,>) message with colors
}