Dark spots

Usually not. Most dark spots are flat, harmless pigment changes from sun, acne, eczema or hormones. The exception is a spot that is new, changing in size, shape or color, has uneven borders, bleeds or itches. Those need a dermatologist's exam, because only a clinician can tell ordinary pigment from something that needs treatment.

Not quite. The flat brown or red-brown marks left after a pimple are post-inflammatory hyperpigmentation: extra pigment, not damage to skin texture. True acne scars are dents or raised areas. The distinction matters because pigment marks often fade with time and sun protection, while textural scars generally need in-office procedures.

No. Melasma is one specific cause of dark patches: larger, blotchy areas often on the cheeks, forehead and upper lip, linked to hormones and sun or light exposure. Dark spots is the umbrella term that also covers sun spots and post-acne marks. Melasma tends to be more stubborn and can return after it fades.

Some do. Marks from acne or eczema often fade over months as skin renews, and faster with daily sunscreen. Sun spots and melasma rarely disappear without treatment, and UV exposure can darken any of them. If a spot hasn't budged in several months, that's a good reason to see a dermatologist.

Sometimes, but not at home. Dermatologists use liquid nitrogen cryotherapy on certain sun spots, and it can leave lighter or darker marks of its own. A clinician should confirm what the spot is first, since freezing something that needs a different workup is a bad idea.