My mom doesn't believe I still need crutches?

I was misdiagnosed with tendinitis about two weeks ago. At a followup appt, they said I have Severs disease. I had something else, but I didn't know what it was. The doctor told me to use crutches as needed, but my mom didn't believe that I needed crutches. She got them for me, but took them away after last week. My family and I went up to a ski lodge this weekend, and I can't set my foot down. My mom thinks I'm faking it! How can I convince her how much it hurt?