Consult with a musculoskeletal physicaltherapist.It seems like starting stage of corn foot,when seeing the picture from my perspective.so if necessary consult a dermatologist.
Next Steps
Look for your slippers,how long it has been changed! Your socks cleanliness etc.
Health Tips
Dip the leg till ankle in warm water/Mild finger kneading can be attempted.If pain aggravates consult a nearby physician.