The nail cap of the thumb hurts when you press it, and it could be an inflammatory reaction under the nail. Inflammatory reactions under the nail are mostly the result of trauma. In addition to trauma, there may also be localized infections, especially under the nail, or skin damage secondary to periungualitis or onychomycosis. In this case, antibiotic treatment is usually needed first, antibiotics can be oral roxithromycin, or cefprozil, cefixime and so on. Topically, you can use Saijin ointment to apply externally, or you can use Jinhuang San to apply externally, or ichthyolite ointment to apply externally. You can also take appropriate oral Chinese patent medicines, such as clearing heat and detoxification syrup.