[dionidium]

In my first job after college (circa 2007) I got roped into maintaining a ColdFusion website, enhancing a billing system written in C, and, later, working on a Java 1.4 app (which was starting to feel ancient, even then).

I learned something useful from each of those projects. And it's certainly not the case that this work caused my other skills to rot.

If you really, really don't like the work, then there's no shame in admitting that and moving on. But you have nothing to actually fear.