Random pop up message while using TikTok on iPhone

I was watching a tik tok and all of a sudden my screen darken. On the Bottom of my screen it had “accept” and “decline” like when a phone call comes in but in blue writing (not the usual green/red button, they were just words on the screen)

it only popped up for 5 seconds so I didn’t get time to fully look at it but it something on the lines of “send this message” or “ someone want to send you a message”

this has never happen to me before and idk if it means my phone is hacked?

11:45pm - 09/12/2022

[Re-Titled by Moderator]