Nerve pressure in the wrist or neck, excessive use during pregnancy, vitamin insufficiency, or swelling following pregnancy can all cause numbness in the middle and ring fingers. Repeated hand positions might also cause nerve strain because you are nursing and taking care of a 5-month-old. When at all feasible, try resting the hand; avoid bending the wrist for extended periods of time; stretch gently; and consume wholesome meals that are high in calcium, iron, and vitamin B12. Please contact a doctor or dermatologist if there is a rash, colour change, pain, or spreading skin changes. The "guilty skin type" you referenced is not quite evident from the letter, and I am unable to view the photo here. If the numbness worsens, results in weakness, or interferes with everyday tasks, get medical help as soon as possible.