When I operated on my first chicken with bumble foot I thought the same thing - looked fine under the scab. I had to keep soaking her foot in warm epsom salt water, cutting into with razor blade and squeezing before "stuff" finally started coming out of foot. When the core popped out it looked exactly like a zit and popped out - small white hard core.
I've had the great fortune
of recently having to operate on both of Ruth's feet for same thing. The first foot was same as other hen, had to repeatedly soak, cut, dig with tweezers, squeeze, repeat but finally a HUGE core popped out - looked and felt exactly like a hard, dry kernel of corn. I wash with Betadine, stuff hole with neosporin, wrape with vet wrap, give 1/2 - 1 cc of penicillin for a couple of days. The next day I operated on her other foot. Got two "corn kernels" out but could still feel a hard one between her toes in that swollen spot that would not come out through the pad no matter what I tried. So I made a slit right across the top and out it popped, no blood, no gaping hole - much easier. She had three of those huge hard things in that one foot - no wonder she was walking like her feet hurt and picking them up and putting them down.
I remove the vet wrap the second day and wash again with betadine and found by third day they were healed.
What we won't do for our chickens. If you told me a few years back that someday I would be regularly operating on chicken's feet on my kitchen counter I would have called you crazy. Thus far, it's been procedures for bumble foot, egg bound, water-filled, stitched up and the list keeps growing.
Good luck. I did find they are really calm especially if you put a towel over their head so they can't see. Then they lie quietly on their side while you cut away at their feet - it's really amazing - they must have a high tolerance for pain or little or no feeling in their feet.
I've had the great fortune

I remove the vet wrap the second day and wash again with betadine and found by third day they were healed.
What we won't do for our chickens. If you told me a few years back that someday I would be regularly operating on chicken's feet on my kitchen counter I would have called you crazy. Thus far, it's been procedures for bumble foot, egg bound, water-filled, stitched up and the list keeps growing.
Good luck. I did find they are really calm especially if you put a towel over their head so they can't see. Then they lie quietly on their side while you cut away at their feet - it's really amazing - they must have a high tolerance for pain or little or no feeling in their feet.