how to get long hair over a week/or a little more?

My hair started thinning when I was 18 and I have always had a very dry scalp. I bought argan rain

wash it frequently

Hair grows at a predetermined rate. It's about 1/2 an inch per month (but varies by individual). That being said, nothing you do will significantly change that rate. The other thing to consider is that once you hair leave the follicle, it's dead (that's why it doesn't hurt to catch it) so you're treating something that is dead and can't make use of the vitamins and minerals you give it. You can possibly soften it to minimize breakage but that's about it. Especially in the summer, the sunlight, chlorine from pools, etc is all very bad for your hair.

Buy a wig.

Idk