the screen went big and I can't reset it

Does the display appear to have zoomed in too far? If that is the case, then you can DOUBLE TAP the screen with THREE FINGERS and see whether that returns the screen to normal and actual size.

If that does work then, Try and Force Restart your iPhone EXACTLY as shown below and see whether that resolves the issue:

• Press and quickly release Volume UP button
• Press and quickly release Volume DOWN button
• Press and Hold the SIDE button until an Apple logo appears and then release the Side button (Can take up to 20 seconds. (DO NOT release Side Button when invited to Slide Power OFF). 

Axel F.

How did you try to reset? It sounds like you restored the phone to factory settings or erased your eSIM. The correct way to unzoom the screen is to double-tap it with three fingers. But its too late for that now.

SOS means that your phone is working, but is not connected to your carrier’s network. It can only make emergency calls on other networks. You need to contact your carrier to resolve this. Here is guidance from Apple→If you see No Service, Searching, or SOS on your iPhone or iPad