Car accident

Hi guys I just wondered if any of you can help - I was involved in an accident that WAS MY FAULT which im very sorry - it wasnt a major accident and the person I smashed into was 100% ok.. but now I realised their claiming for lower back injuries... is their any way I can stop this from happening as I know deep down they was ABSOULTELTY FINE!

Can you also let me know how much they will roughly get and HOW LONG does this kinda thing take? thanks guys!