Normally, you are supposed to let the liquid or foam settled or dried in hair (normally takes about an hour or two) before you can style your hair any way you want.
However, it is written on the box that you should apply the minoxidil liquid or foam {twice} a day. So, you have to plan on how to apply it, and then styling it. (For me, I only apply once a day since I have had several HTs now, and my hair is fuller now. I don't need to apply it more than once a day to maintain the transplanted hairs on my head.)
Wishing you luck and on your coming HT.