Niner, I would show you my face in photos after 4-5 months of the strongest formula 2xdaily, and perhaps you would eat your words. At 25 being told one day that you look 19 and the next day literally having someone ask you if you are 35+ is a very odd thing to happen normally. Perhaps I'm an anomaly because I have extremely fair and sensitive skin. Even though the study is not in vivo, I can attest to it's potential damage, and I still think it's fair to put that warning out there so at least people can be aware of potential consequences.
I'm sorry that you had to go through that experience, which sounds pretty awful. The problem is that you don't really know it was the minoxidil that caused it, only that these events happened around the same time. If the minoxidil did cause it, you don't know if it was a collagen effect; maybe you're allergic to something in minoxidil?
The only in vivo paper I could find on minoxidil and its effect on collagen is this one:
J Cardiovasc Pharmacol. 1998 Jun;31(6):960-2.
Arterial vasodilation and vascular connective tissue changes in spontaneously hypertensive rats.
Tsoporis J, Keeley FW, Lee RM, Leenen FH.
Hypertension Unit, University of Ottawa Heart Institute, Ontario, Canada.
Arterial hypertrophy in response to hypertension includes increases in the connective tissue proteins elastin and collagen. Regression of arterial hypertrophy depends not only on blood pressure normalization but also on the specific antihypertensive treatment. Consequently, each drug class may exert an influence on connective tissue proteins. We evaluated the arterial connective tissue response of 16-week-old spontaneously hypertensive rats (SHRs) to treatment with minoxidil, 120 mg/L, drinking water for 10 weeks. Despite a decrease in blood pressure, minoxidil had no effect on arterial weight or collagen content but increased elastin content in the abdominal aorta, renal, and superior mesenteric arteries. The increase in elastin content in the abdominal aorta and superior mesenteric artery was accompanied by a decrease in tissue elastase activity. Thus the minoxidil-induced increase in arterial elastin content may be related to a direct effect of the drug to decrease elastase activity in these tissues.
PMID: 9641483
So if anything, it sounds like minoxidil should improve skin quality, if it increases elastin and has no effect on collagen. Realistically, I wouldn't expect any systemic effects from topical application of minoxidil. It doesn't have a significant effect on blood pressure when used topically, and since it was originally a medicine for hypertension, that was the first thing they looked at.