Stop A Mass Text? View Mass Text History?

I downloaded the Mass Text Shortcut App. I have a business that I had to change my phone number for. I thought it would be an easy way to let all my clients know my new contact info. Well, I severely messed the message up and pressed send after selecting all my clients. I freaked out and turned my phone off as soon as I could! I then started my phone and deleted the app ASAP! It did go out to some people, but I don't know how many? I am absolutely embarrassed! I would like to know who all actually got the message, but none of it shows up in my sent txts! What can I do to see who all got it and try to mitigate this damage?!