You may instrument your files as many times as you like. The first time you do this the originals are copied to the revdsrc/ parallel directory tree and each subsequent time they are instrumented from there.
This means that if you want to edit your original source file after instrumenting you should do it in the revdsrc/ subdirectory. When you execute revd --remove
the source files are copied back from this subdirectory to their original location along with any changes you made in the revdsrc/ tree.