Restarting a Course Challenge

I would like to suggest the ability to restart a course challenge. I completely understand that that's the "challenge" part of it, but I have spent days working on receiving so many crowns and now they're all gone. As a perfectionist, I do not like seeing anything be wrong, so I usually restart a lesson if I get a question wrong. I was attempting to do the same with the challenge, but I learnt that I couldn't. That is why I decided to press "skip" on all the remaining questions so that I could restart, only to learn that all the crowns I had worked so hard for are now gone. When I tried to earn it back, my anger (which usually causes me to have poor logic) caused me to fail the challenge over and over again. I would like to suggest you guys to add a restart button, remove the level down, or at least warn me first that I would level down if I answered too many questions wrong. This strongly upset me, and practically ruined my day.