Muscle Rub...Yay or Nay??

I have a major knot on my lower back on the right side. Every time I move, I can feel the muscle pain... to the point I'm in tears!! My boyfriend tried to help rub the knot out and used some muscle rub. I'm freaking out because I'm not sure if it was okay to use??? Everything I read online gave conflicting answers. so I ran to the shower to wash it off!! I'm just about 6 weeks along and worried I could have harmed the baby because of the muscle rub... #feelinglikecrap