Can hair gel cause hair loss?

No, putting Rogaine on one area will not cause other areas to lose their hair. Most commonly there is some shedding in the immediate area it is applied temporarily, before stimulating more growth in general. 

Yes, alopecia areate can be limited to the eyebrows.  A steroid injection can help resolve this situation in many but not all individuals.  One should not inject a high concentration of steroids for alopecia areata because this can cause depressions of the skin.   

If you want to know how to treat your hair loss and the best approach, see a good doctor experienced in this field.  Good doctors do not make such recommendations over the internet that are not customized to your individual needs

In general, medications that are more effective at preventing hair loss and/or helping hair growth are also going to leave you more prone to side effects. So, something like Minoxidil works really well but relatively is more likely to cause irritation or (rarely) heart problems. Something like...

By your account, minoxidil seems to be helping as you are seeing hair sprout.  Finasteride has been reported to work best on the crown.  Patients often use both medication together as there are reports of a small but added benefit when used together.  See a hair restoration surgeon to discuss yo...

There are other options but generally Finasteride has been proven to be the most effective in preventing hair loss. If you are really concerned talk to your doctor about alternatives. However, it's worth noting that the large majority of people (over 90%) that take Finasteride don't report any...