In-between bleach touch up?

I have short, bleached hair.

I like how it looks at all stages before I need another cut (pretty short, and then when it grows a bit)

I get it cut and bleached every 4-5 weeks.

I love the way it looks that last week, except that the color gets a bit dull or yellowish. I do use that shimmer lights shampoo/conditioner once in a while.

I was wondering if it makes sense for that last week if I were to do a quick touchup. (bleach roots for a few min, and just before washing just swish the bleach all over my hair for a few seconds to touch it up)

Would that damage my hair if i go to the salon a week later?

By the way i am talking about hair bleach (purple stuff) , not sure what brand my salon uses though.


Thanks