If you believe you have a side effect from minoxidil see your doctor for an exam. If it did cause your skin pores to enlarge it should reverse after stopping.
If you believe you lost eyebrow hair due to a thyroid condition, you should treat the thyroid condition. You need to see a doctor for a proper exam and treatment options.
Minoxidil is not available in 10% or 15% in the U.S. unless a doctor specifically prescribes them. More (higher concentration) does not mean it works any better.