Is there any way to reduce the space under my upper lash line / eyelid margin?

You have ectropion of the waterline. You actually have upper eyelid ptosis and a poorly controlled eyelid platform. Effectively the eyelid platform are asymmetric (too much platform show on the right side). To address these issues, a surgical revision is needed to lower the eyelid crease, correct the ptosis, release the current scar tissue that is causing the waterline ectropion. If you are using a lash growth product like Latisse or an over the counter product that contains isopropyl clorprostenate, or castor bean oil. These products do in fact grow eyelashes. The ingredients are prostaglandins that stimulate eyelash and eyebrow hair growth. You may have head of eye color changes caused by these products-they seem to be rare unless you are using a prostaglandin glaucoma drop. Much more common, perhaps 70% experience loss of eyelid volume after even 6 weeks of consistent product use. It was first thought that these change would reverse if the product is discontinued but it is likely. However it appears that these compounds kill eyelid fat and cause scaring. So if you are using these types of products-stop now before more harm is done. Your eyes can be your best feature. There is no substitute for a detailed in person assessment.

You really need an in person consultation with an eyelid expert to discuss you goals. They eyelid margin usually isn't the problem and if it can be hidden with make-up that is often the best solution. Eyelid height can obviously make a person look more tired. Best to see an expert in your area. Best of luck!

The area that bothers you is very functional area of eyelid that carries different glands that produce different components of tears. Creating scar on this area would possibly compromise tear production and quality. For that reason I would not recommend this type of surgery.