Too much Minoxidil can do any harm?

[Floyd77]

I have made a second HT 24 days ago and have started using a manipulatted minoxidil formula without propylen glycol. The problem is I have lots of hair and it's hard to apply it in a way I can assure that all parts of my head that are propense to shedding are covered. So I apply lots of Minoxidil. I think 5 or 6 ml each time I apply (I do it twice a day). Can all this Minoxidil do any harm to my hair or health? If it does, please tell me how to apply this thing if I have long and full hair. My dermathologis said it's not necessary to rub it into the scalp because most part would stay at the fingers or hair but I don't share his opinion. So to be completed covered I first apply rubbing and after just drop it. This is a stupid way to do it that's why I'm here asking for your opinions.

I have ordered Foam but I think it would be more difficult to apply than the liquid.