Could this be why my Heat desn't work well?

Shot in the dark here, but when I removed my AC, I [very crudely] cut the hard A/C lines that go into the firewall right around the heater core. They are all jagged and bent up. I think I stuffed a ball of masking tape into one of the exposed tubes...
Anyways, I was just wondering if these interfaced w/ the ducting of the heating system in any way that might make for a lack of heating ability, as my heat will blow semi-warm, but not hot, even after back-flushing my heater core until it ran clear.....
Thanks guys.
P.S. My next alternative is to buy a portable heater fan and a power inverter because it is unacceptably cold some days, and it's only getting worse.
Fire hazard, anyone?!?!

which one is the blend door? Right above the passengers feet, I can see the big door that opens when you turn the vent "on". Is there another door too? If so, where's it located and how can I check the operation?
"IOW", what's that stand for?

Thanks for the interpretation.
Now, how bout that Blend door? Is it the big one on the bottom or another one I haven't checked?