It’s crucial to note that, sometimes, nail discolouration is a symptom of an underlying health condition.

Yellow-brown spots under the nail could be due to psoriasis, white on the bottom half and pink or discoloured on the top could be indicative of kidney failure, completely white could be cirrhosis, and green could be down to pseudomonas infections

Healthline suggests seeking medical attention if your nail or nail bed:

changes in shape
thickens
bleeds
swells
is painful
has discharge