thanks for writing to health care magic.
It seems you have devolped fungal infection
of your nail.
Splitting of nail allows fungus to colonise in it and grows in it.Growth of fungus causes whitish and raised appearance.Pain may be due to secondary infection with bacteria.
Fungal infection of nail needs oral antifungal
drugs like terbinafine ,itraconazole
etc.You need to consult a dermatologist
for it and take treatment accordingly.
Hope this can solve your query.Take care.