The bump could be a chalazion which most often does not go with medications and requires incision and curretage which is a minor surgical procedure. Dexamethasone is a steroid and you should not use it for long otherwise you can develop cataract, glaucoma e.t.c. The treatment that you are taking seems to be correct however you should also use a lubricating eye drop like Refresh Tears 4 times a day. Dexamethasone should be gradually tapered. You can give the bump 2 more weeks. If it does not go, then get it operated.
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