I have below the shoulder length hair, very fine strands but very full head of hair and easily tangled. I have tried going at my head every way I can think of to try to get the medicated shampoo on my scalp where it's needed. I just end up basically rubbing hair on more hair (like folded over or piled up) and hoping it's somehow reaching my scalp. Please any suggestions how to get shampoo on my scalp better? I can't take a long time doing it, due to health issues I can't have my arms up long. Example - I tried parting smaller sections to try to get in as many "parts" I could make to try to get shampoo directly on scalp, but it took a very long time, I ended up still tangling my hair, and had to use extra shampoo this way- and couldn't raise my arms for the next couple of days. I need a quicker method please.