My 4 Year Old Daughter Will Not Walk. We Went

My 4 year old daughter will not walk. We went to the fair Friday, Sunday she couldn't walk so I took her to urgent care Monday. They said she had DOMS and she was just sore from walking around. They gave her Motrin while we were there and it helped because she walked out of urgent care on her own and was walking fine Tuesday. Now today, Wednesday, she will not walk again. She's screaming saying her legs hurt again and she won't even try to stand up or bend her legs