What are the possible consequences if someone shows police a text message showing me confirming I still use drugs?

My ex is pregnant and trying to do whatever possible to either get me in trouble or limit or deny my visitation rights with the child. She also mentioned trying to put her last name on baby and sign up for child support. Is that even possible? Doesn’t it need my last name in order for a court to approve child support? Anyhow, she also has saved text messages of me with my boys. She has one text where I sent a pic of the cocaine I had. I don't appear in background, but it is my phone messenger where she's been screen shooting these conversations. Another image shows me asking for coke and how much I need. Another screen shot of my boy asking me if I still use cocaine and I say yes. Brief background of me: I am an immigrant and am here illegally. I have several past record of drug use. What am I facing?