“(null)” is Using Camera Access to Control Connected Cameras

Go to Settings and check all the apps that are using Camera. Delete the apps which is not required by you anymore.

iOS / iPadOS devices cannot be hacked or infected with Virus / Malware / Spyware if it is updated to latest iOS/iPadOS, unless you have intentionally downloaded spurious softwares or unauthorized apps directly from the internet and installed on your device or/and have Jail Broken. 

It (Hacking) also depends on how careful are you in sharing sensitive and valuable information pertaining to your iPhone such as Passcode, Password etc with your friends and family members.

Be careful when sharing the device's sensitive and valuable information with friends and family members.

Thumb Rules:

1. Enable  Guided Access before handing over an iPhone to kids
2. Don't share Apple IDs
3. Don't Jail Break
4. Don't share sensitive information pertaining to your device and payment methods
5. Beware of Phishing

That happened to me but my phone shut down itself for 10-15 seconds which scared me please help me I’m so scared if some have my pictures