What should you know about a green cyst under the skin?

A skin cyst is a closed sac beneath the skin. It can become tender, swollen, warm, or red when inflamed. Green fluid, a green surface, or an unpleasant smell can suggest infected drainage, but colour alone cannot identify the cause. A lump may also be a different type of skin lesion. Do not squeeze, pierce, or try to drain it at home; pressure can push inflammation deeper and spread bacteria.

A clinician may inspect the lump and the surrounding skin, ask how quickly it changed, and decide whether it needs observation, medication, drainage, or removal.

Keep the area clean and covered with a fresh dressing if it is leaking. Wash your hands after touching it, avoid sharing towels, and use a warm, damp compress for comfort without pressing on the lump. Arrange a dermatology or primary-care assessment, especially if it is growing or painful. Depending on the findings, care may include [Abscess Drainage](/treatments/minor-procedures/abscess-drainage/), [Steroid Injection Into The Skin](/treatments/injectables/intralesional-steroid-injection/), or [Cyst Removal](/treatments/surgical-dermatology/cyst-removal/).

Seek same-day medical advice for rapidly increasing pain, spreading redness, marked warmth, pus-like drainage, fever, or feeling unwell. Urgent assessment is also sensible when the lump is near the eye, nose, or mouth, or when you have diabetes or reduced immunity. A nearby [Skin Lumps](/symptoms/skin-lumps/) guide can help you describe what you are noticing, but it cannot diagnose the lesion.

Ask whether this looks like a cyst, abscess, or another lump; whether a sample or drainage is needed; how to dress the area; and what changes should trigger urgent review. Ask how recurrence can be reduced if the cyst wall remains.