Hello,
I cannot confirm a diagnosis without examination,but it can be foot blisters or fibromas.
When a foot is hot and sweaty, the sock sticks to the foot. The sock and foot then rub against each other and the inside of the shoe causing blisters to appear.
Wear shoes that fit properly and keep feet as dry as possible.Wearing wet shoes, boots and socks will increase your chance of developing blisters.So change socks regularly.
And use foot powder to help keep your feet dry.If the blisters still persist then pls get it evaluated from a dermatologist/podiatrist.
Hope it helps.Take care and pls do keep me posted on how you are doing or if you have any additional queries.Warm regards.
More like pompholyx due to sweat gland obstruction.