Hi and Welcome:
Please do not cause yourself too much stress about this diagnosis and your prognosis. I am going to be completely honest with you; you may lose a lot of hair and may go bald in some spots. This does happen to some with Discoid Lupus in their scalp. While others suffer very little to no hair loss at all. It is not the same for any two persons.
I totally agree, Plaquenil is the best medication for the lesions in your scalp. You should know, however, that Plaquenil is a cumulative drug - meaning it can take sometimes weeks to months before you see a significant change. However, once the Plaquenil starts to work, it works very well and, often, the lesions never come back
The other good news is, once the healing starts, the hair will re-grow. This is the rule, rather than the exception. It may grow back as baby-fine new hair at first, but it will eventually get back to a state that you are satisfied with. Again...this will all take some time. So, you may need to be patient and find ways to deal with your hair (wigs, extensions, hats, scarves, etc.) until the healing begins and the new growth starts.
We are here to help you as much as we can and in any way that we can. You are not alone.
Peace and Blessings
Look For The Good and Praise It!