I have what I thought was a blister on my index finger. the skin is calloused from frequent rubbing and now it has gotten red and sore. cannot see any liquid but there is a white area inside the red calloused skin. the size of the affected area is larger than a dime but smaller than quarter. it is on the second joint of the index finger on the outside where it rubs against almost everything. Opening water bottles, Trader Joe s, is impossible cause of the pain.