can you show us pictures?

at minimun, with no pictures...I'd cut
damaged sections & put new ductwrap around
the duct at area removed.
then you'll need to attach new duct
wrap to old. I'd use duct stapler..but
you could just use fsk tape.
wrap it around the duct so that new
tape seals to new tape. do this near
both ends and in center of replaced
duct wrap. (every 4-6")
then use a paint on mastic to seal
the new section to both ends of the
old sections.

not going to last forever, but maybe
you'll decide to unwrap, mastic seal
and re-wrap ducts this spring???

best of luck.