The change for the photos is probably sweat eczema. It is a skin condition that is characterized by the occurrence of itchy blisters and papules filled with fluid, mainly on the hands and feet. It is a non-communicable but recurrent disease, and its causes are not fully understood, although it is often associated with contact allergies, atopic dermatitis or fungal infections.

I encourage you to consult a doctor to confirm the diagnosis and implement treatment. Topical therapies with glucocorticoids are most often used. Exfoliating and softening agents are also used.

If you need more personalized advice, you can use teleconsultations here:

https://www.gdziepolek.pl/telekonsultacja/z-dermatologiem

I have an almost identical button on the side wall of my ring finger. It starts to me off, I don't know what it is???