Hi,
I know that Geranium sanguineum(and probably some other varieties) will rebloom later in the season if sheared back. The after bloom part really doesn't matter. If you do it during bloom, it is the same thing, lol. So it is quite possible that yours may rebloom later: )
Remy

The cutting back of annuals is recognized as a way to encourage re-development of bloom since, by doing so, we stop the plant thinking its job of producing bloom is over and thus, begins to produce seeds.

With perenanisls, that can be quite different....they produce one flowering...and only one. They do not respond the same way annuals do.
So the cranesbill is not a pelargonium...it blooms as it can, when it can and then ...that's it, game over.
Cutting it back while in bloom is not how to force it to create more....or better volumes.

Better to cut it back AFTER blooming to force it to grow more compactly, giving less to create more.

i always cut mine back while it still has some blooms on it....it always blooms again....some other perennials also bloom again after cutting back...the second bloom isnt as nice as the first though.
good luck