My pet chupacabra won't let me pet him?

I got my chupacabra about 4 months ago. I'm becoming really attached to him and named him Josue. However, a couple of days ago I realized that Josue won't let me pet him. He isn't eating his Kibble and Bits either. Oh, and he isn't aggressive. He smiles at me, makes strange chupacabra rumbling sounds, and playfully nibbles on my neck when I hug him. What should I do?