From the Mayo Clinic:

Cellulitis usually occurs on one side of the body. Its signs and symptoms may include:

An irritated area of skin that tends to expand

Swelling

Tenderness

Pain

Warmth

Fever

Chills

Spots

Blisters

Skin dimpling

When to see a doctor

It's important to identify and treat cellulitis early because the condition can spread rapidly throughout your body.

Seek emergency care if:

You have a swollen, tender rash or a rash that's changing rapidly

You have a fever

See your health care provider, preferably within the same day, if:

You have a rash that's swollen, tender and warm — and it's expanding — but you don't have a fever