I would say the tire got bruised badly enough to consider it NFG..
Be careful when you inflate it again,that bubble might pop !..radial sidewalls are pretty weak and dont like side impacts..or going over curbs at speed..
Tires are a constant source of misery for me..seems one or more is always losing air,or has cracks,etc,that make me fear it'll blow out or toss the treads on the highway..haven't had the means to buy "good" tires used or new,so I run whatever I can get cheap or free..
I wasted an entire afternoon putting a used tire on one of my trucks rims by hand,using a bead breaker and tire spoons..one tire was down to the cords and I had another one very close to the same size--a 65 series vs a 70 series 255-16..
I screwed up royally and put the first bead on the rim from the "wide" rear side of the rim--I have mounted tires since I was a teen,yet I still screw up sometimes and do that..

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..took me 2+ hours and lots of straining & cussing to get the other bead on the rim--after all that,when I inflated the tire,it had a huge bulged out soft spot in the sidewall !.JUNK!...
I was beyond pissed..at least the tire was a freebie...but I'm still sore as hell from the battle I had mounting it on the rim..it was an inch smaller overall too,so it wouldn't have been a good match to the other 3 tires,so I ended up swapping another set of 4 265/75/16 tires I had on rims already on the truck...
Those aren't all the same either,all say the same size on them,265/75/16,but two are Goodyear Wranglers with C load rating,the other two are E rated Firestone Transforce ones,and I bet they are slightly different diameter..hope it wont make the truck swap ends in slippery conditions running that combo..
