Botox question, 11s alone or do I need forehead too?

[Readytoevolve]

Hi there, I went to get Botox on my frown lines / 11s this week. This would be my 3rd time.

1st time I got it in that 1 area and it was given my a Dr who trains people in Botox.
2nd, again 1 area, by a new doctor. All good

3rd time this week, the dr refused to so just 1 area because she said it would cause my issues longtern and that I needed to do forehead too…. I did do end up doing the 2 areas but I’m baffled by this and annoyed that i wasn’t given this advice before.

is it true? Do I need the 11s and forehead done together to prevent extra issues with my forehead muscles long term.

I have a very pronounced 11s frown, started botox about 4 years ago. In the beginning I got only the one area done and it worked amazingly well. I now have to do 2 - forehead and 11s - as my forehead muscles compensate and pull my 11s in. I think if you paralyse 1 area, over time you will need to do another area that is trying hard to compensate. I suspect one day I will just have to freeze my entire face.