Hopefully, you only make this mistake once if at all. Your first brow wax. What happens when you remove too much hair? The first step is to be honest with the client. Show them in the mirror. The majority of the time, they will be forgiving and may not even be as upset as you are at the error. We tend to overanalyze our work. Trust me. I still do it. I usually have on magnifiers, so it's really hard to see how the shape actually looks until I get up and walk around to view the client right side up. The second step is to offer the service for free. This will be no charge since I did not deliver exactly what you requested. Please allow me the opportunity to make it up to you next time. You can even offer a secondary treatment as an add-on. When you meet your clients with a giving heart, you will find they will do the same. Remember the four agreements. Be Impeccable With Your Word, Don't Take Anything Personally, Don't Make Assumptions, and Always Do Your Best, promising greater freedom, happiness, and love.