Is there any way to get rid of this chalazion/ scar tissue once and for all? (photo)

Seeing a fellowship trained oculoplastic surgeon with well worth your while to help get this resolved.  While general ophthalmologist do treat chalazia, eyelids are not their practice focus.  The American Society for Ophthalmic Plastic and Reconstructive Surgery maintains a geographic directory on their website that will help you find a well qualified surgeon to help you with this issue (ASOPRS dot org).

While there is a low likelihood for an eyelid tumor or cancer, I would suggest a biopsy to cover all bases. The abnormal area of eyelid/glands can be surgically removed altogether, but I would suggest seeing an oculoplastic surgeon who specializes in removal of lesions of the eyelid to ensure the best aesthetic result.

You should get a biopsy of it first, to make sure it is in fact a chalazion. Once it is confirmed, the injection of Kenalog 40 into the scar will significantly reduce the lump.

Sometimes, it may take multiple procedures to completely treat a chalazion. Even when the chalazion is "cut out", it can recur, which is very frustrating for the patient and doctor alike. Kenalog is often used to treat chalazia, but one of the main risks is permanent skin depigmentation (i.e., it can turn your skin white). 5FU is another alternative, but that is an off-label use. Hope it goes away soon!

Some larger chalazia take time to settle after incision and curettage surgery and there is a residual swelling and inflammation. If there is ANY doubt that it is a chalazion, then a biopsy must be taken for histopathological examination to exclude meibomian cell carcinoma. Some large chalazion recur or partly persist as  they are loculated and require a longer incision or repeat incision and curettage. Mostly there is a residual swelling with redness that can settle either with topical antibiotic steroid cream or small injection of kenalog. An oculoplastic surgeon can look under the eyelid to see if there is the tell tale sign of a grey creamy swelling on the tarsal conjunctival aspect, which confirms a collection of fluid gel within the meibomian cyst, which is suitable for further incision. 5FU (5 fluorouracil) has been recommended as an injection for the treatment of chalazion, but it often requires more than one injection. From Miss Jane Olver, Oculoplastic Surgeon, London UK

What is left behind appears still quite sizable. It may get a little better with time but you may need another procedure to remove the residual scar tissue and whatever is left behind. Sometimes these can be stubborn and re-accumulate. Surgery along with medication or Anti-inflammatory Injections can sometimes be helpful. Sincerely,

These can be prone to recurrence, but if they keep coming back in the same location then they should be biopsied as cancer tissue can cause chalazia.  I would recommend an oculoplastic surgeon for evaluation.