I did the update yesterday to 1.20.1201.0 and ever since, my 8yo has been really frustrated. 
In each of her worlds, she can’t see her hands/ arms, her inventories and food bars have disappeared, she can’t change skins and I don’t have any experience to assist her. I’ve Googled the issues, but there isn’t anything helpful online. Has she just pressed something she shouldn’t have that hides things or is this a bug?

please could someone help me?

thank you!