My nails have been changing shape very gradually over the years I have been sick. I think many of us have fingernail and toenail changes as part of our illnesses. Ridges, changes in color and density, changing from one general shape or orientation to another.... It's all part of the package. You could take biotin or other supplements to strengthen nails and combat nutritional deficiencies, but to remedy the changes, your overall health must improve. Some practitioners who are into heavy metals see nail changes as indicative of metal toxicity as well.