I used my best friends credit card and i need help at getting his friendship back?

well i stayed at his house and i just tried to use my card but it wouldent work and i wasent thinking so i just used his it was only 20 dollars but i feel soooo guilty about doing it im loseing my friends that i met because of him and i dont know what to do i just feel sooo bad he was one of my only friends i could go to for help but the trust is just gone now so plz help me.