It might not matter in your case, but this will only catch comments that start and end on the same line, as the '.' does not match the newlines.
You can try these:
$question =~ s/\*.*?\*//sg; # the s modifier causes . to match newlines
or
question =~ s/\*[^*]*\*//sg; # [^*] matches the newlines too
Update: added a * in the second regexp (thanks swiftone) and removed the (), you don't need to capture the comments.
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