a) Infection related causes
Fungal, bacterial or viral infections can all cause redness, swelling, tenderness and an abnormally shaped nail fold. They may or may not co-exist with changes in the shape of the nail itself. Treatment times can be very varied as some infections take longer to clear than others. This is usually collectively termed paronychia.
b) Inflammation related causes
Conditions affecting this fragile skin adjacent to the nail plate can include eczema (both irritant and atopic eczema) and psoriasis. Treatment would need to be directed to the underlying cause to allow the finger tip to improve.
c) Other causes
Habitual tendencies such as habit-tics or finger sucking also contribute to nail fold and cuticle issues. These tend to settle as long as the external physical cause is stopped.