It may be that you have underlying dry eyes, and that the change in your eyelid function [abnormal blink] or eyelid position [in ability to close the eye fully] may have lead to your current situation.
If you decide to explore this further, I would recommend consultation with an ASOPRS trained Oculoplastics surgeon. You can find one close to you on the ASOPRS dot org website
Extremely Dry Eye after Blepharoplasty is not Normal
I am sorry your are experiencing dry eyes after your blepharoplasty. Patients that have dry eyes before a blepharoplasty are a risk to developing drier eyes after surgery. If a patient has dry eyes before a blepharoplasty, I send them for special tests to ensure they are able to make enough tears. If they can make enough tears then they are not a candidate for surgery.
In your situation, it is hard to tell you what is going on without a picture. If the surgery changed the position of your lower lid to a point to where it is not in good contact with your eye, it can cause your symptoms. There are a variety of other causes that can cause your issue, and you need to see a qualified eye specialist to ensure you eye is in good health.
I hope this helps.
Dry Eye After Blepharoplasty
Sometimes eyelid surgery can cause dry eye by changing the positioin of the eyelid on the eye. I recommend you see an oculoplastic surgeon (eyelid specialist). You can find one at the website ASOPRS(dot)org.