Missiles cowl repair needs help

Here are the pics of the repair.
The firewall pieces were easy. But the cowl sheet metal buckled the first time and after removing it again and taking ANAL care not to heat the metal up past 105 ( the ambient temp) it buckled again but not as badly. portions of it have the feel of the top of a canning lid. Does anybody know how to get rid of the built up pressure, or fix the problem?

Attached Images
Author: admin