"Overexaggerating" is redundant anyway. Just say exaggerating. And if "Stop exaggerating" doesn't fit, "Calm down", "Chill out" and "Relax" would've all been better phrases to put than outdated slang.
Now that I think about it, the funniest part of this all is that to cap simply means to lie, to be untruthful. So out of all the ways you could've translated what was written, not only did you use outdated slang, you used incorrect outdated slang.