Brief Answer:
Please consult an Ophthalmologist

Detailed Answer:

Hi,

Greenish swelling below the eye with itching and red inside can be due to allergy, unnoticed trauma or infection. These are the common causes while other less common cause can also lead to this condition.

After going through the details, it's not conclusive to identify the exact cause. The treatment depends on the cause and symptoms.

In most of the cases putting decongestant drops with antibiotics help.
But in this scenario, I would request you to get her evaluated by an Ophthalmologist urgently.

I hope this helps.
Please let me know if you have any more questions.

Regards

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Brief Answer:
You may use antiallergic/decongestant combination drops

Detailed Answer:

Hi,

You can use antihistaminic and decongestant combination eye drop like Naphazolin and pheniramine maleate after consulting an ophthalmologist.
The decongestant decreases the redness and antiallergic takes care for allergy if any and itchiness. Sometimes prophylactic antibiotic drops like moxifloxacin or tobramycin are also given to prevent any secondary bacterial infection.
This can be used four to six times a day depending on the severity.
Avoid rubbing the eyes and watch for any further worsening like increase in swelling, pain, redness or disturbed vision.
If you notice any deterioration please consult your ophthalmologist immediately.

I hope this helps.
Regards

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