State witness

I was in a asian massage parlor recently. Nothin happen except the usual . When I left the place I was pulled over by the police. I asked what I did wrong and the officer told me I did not use my blinker and I said to him I am pretty sure I did. We'll he asked me how my license was in standing and it old him it was clean. Than the officer asked me what went on in the parlor and I told him it was just a massage. He kept pressuring me and told me nothin would happen to me and he gave me his word. Do I told him what I told you above and he told me not to come back . Now the real question this week I got a notice to appear for the state as a witness aganist this girl she is being charged with prostituion and please not guilty. Can I get in trouble  for telling the judge what I told you and the cop . Do I need a lawyer and do I have to attend?????