How can I sue for a wax burn?

I have had my eyebrows waxed before but I have never had my chin waxed. The nail salon I went to they said they can wax my eyebrows,lips and chin. When they waxed my chin they waxed it twice. I don't think the lady knew what she was doing when she did it. That night when I went home it was red like it should have been but the next day I woke up and had what looked like razor burn on my chin. My sister's wedding was 2 days after I had it done and it was still there I took pictures of it and now 4 days later it has healed some but now looks like I have scars from it. I spoke with a friend of mine and she said that because they didn't make me sign a waver or give me a consultation before hand that I would be able to sue.Is that true?