When I have panic attacks, I have a really hard time getting a full breath and swallowing. I don't find paper bags helpful, because for me it just reminds me that I am trying to breathe, instead of remembering that it is an involuntary bodily action. My body knows it needs to breath and swallow to stay alive. My anxiety is trying to convince me I have to be in control of it. So I find, for me, distraction is the best policy. I will post on social media and ask people to post stupid pictures of cats or dumb jokes. You wouldn't believe how much people love posting stupid cat pictures and dumb jokes. It seems silly, but that's the point. Even when the impetus for a panic attack is happening or true or seems real, there still is silly and happy and goofy and funny and all the other positive emotions inside of you. Reach out and let other people help you draw them out.
It's like breathing into a paper bag full of giggle gas. :)