I didn't know what this patch was so I went and looked it up.
I read a few things that caught my eye.
First, it numbs the skin... She's still going to feel pain since muscles are usually sore after a shot.
Second, it said all the doc if you are using before a vaccine. Some vaccines can react poorly to it or it can affect the vaccine.
Third, it says do not use if you are pregnant. I know it's not going on you but I still wouldn't feel comfortable with it. You will have to apply it and handle it.