It can be a bit startling, to get an incoming call from your own number and see your own photo staring back at you. But if you get a call like this, the safest thing to do is not pick up.
There's a scam going around the Lubbock area, where people pretending to call from your own number claim your account has been "flagged for security" and ask you to enter the last four digits of your social security number.
This scam is affecting multiple carriers. We have reports of AT&T and Verizon so far, with multiple people reporting phishing attempts on social media.
No authentic carrier will ever call and ask for your social security number. It's a bad idea to give out your social security number to a caller under any circumstances. Even if you think the call is legitimate, it's always best to call back at the official number listed by the business (not a number they give you over the phone) and initiate the call yourself.
If you're concerned about someone gaining access to your account with your social security number, carriers will allow you to set a passcode to access the account instead.