Takes a long time to see results. Bad side effects

My lashes are pretty short to begin with, so I looked into a few brands of lash serums and decided on this one. I applied the serum daily as instructed and started to see a noticeable difference after 1.5 months. Afterwards I started using the serum only a few times a week (as instructed). My lashes were noticeably longer at the 2 month mark, but were still pretty weak and would break easily. If I went 3-4 days without applying, my lashes stopped growing and looked the same as before due to the shedding. After discounting use completely I had a stye (for the first time) at 27 years old, my eye was extremely red and swollen. After seeing a doctor I believe that the serum caused the stye. Shortly after getting rid of the stye (2 days after)I had another on the same eye but a different spot. Once the second one started to go down my eye has been irritated in another spot. Please be aware of these side effects, it is mentioned no where.