Hello,
Thanks for posting your query at DoctorSpring.com. I can understand your concern.
It seems to be a condition called pompholyx. It's an eczema, which is seen more often in winters.
The treatment would be application of a steroid cream like mometasone twice daily.
The cream would require a prescription.
In the picture, it doesn't seem to be warts or callus.
Hope this helps, Please let me know if you have any queries.
Take care