Daughter lying i need advice.

I had my child taken away from me when she was 6 months old and placed with her grandmother. The allegation was false but cps dropped the ball on the case and I didn't get visitation for a year and eight months, the grandmother has half custody and has been taking my child over to see my child's father, grandma's son. CPS showed up on Thursday, when i was dog sick, and asked me some questions about bruises on my child and a rash. She didn't have any bruises or a rash when she left my house and I told the cps lady that what my child said was a lie. The cps lady left and i think she believes that my daughter was lying about where she got the bruises. Now that i have my child back at my house she showed me with out prompting the rash and the bruises and told me where she got them. The bruises were no big deal because she got them from tripping over a branch in her grandmothers yard. but the rash she got from her father touching her in her girly parts. I don't know what to do because if i take her to talk to cps then they will think i coached her to say that, because i have called in on him before because i thought he did something to her. I believe this was the grandmothers plan cause my child also said she told grandma what had happened and grandma didn't believe her. Then grandma called cps and told my child to lie about the rash. Grandma is in denile about her son and his mental problems but to allow a child to be sexually abused to server your own ends is evil! what can i do about this? please help!