If it stays puffed up after all threat is removed and the toxins have dispersed, say 24 hours, it could be an anaerobic bacterial infection which generates subcutenaceous gas, or an immune system over-response. Wait and see.
I'll check tomorrow, I've moved her into a 10 gallon tank, but I wasn't prepared for a toad, so she's on paper towels for now. She seems happy, but her neck is still all puffy. I'll post more pics, hold on.
So, the puffy part on her neck/chest went down a little bit, she let me touch her back and sides without problem, so I would assume that there is no pain there, however, as soon as I touched the puffy area, she started freaking out.
Maybe, I probably should of specified that I found her on an ant mound. Either way, I'll try to do extra research, Other than the puffy neck though, she's pretty active, hunting the crickets/waxworms I put in there. Anyways, helpful as always, Snark, thank you all for all the great advice. If you need me to, I'll post more pictures. Although, something I noticed, is that on one of her front legs, there is a little abrasion/spot, not sure if toads normally have a pink/red area on their foot or not, as I've never owned a bufo species before.
Toads are highly resilient, often termed the survivalists of the amphibian world. Some even go broader, the survivalists of the animal kingdom. Keep it well fed and stress free and put your trust in it's durability.