Are there topical antiandrogens I can use instead of taking something internally such as finasteride?
Yes. Some things have been used topically to either bind up receptors (Spironolactone or estrogens) or reduce androgens or diminish hormonal impact (azelaic acid, pyridoxal B6, zinc, free fatty acids). There is much debate about the efficacy of these agents. The problem is a lack of study data regarding their use in pattern loss, though there are studies suggesting why these agents may help.