Not sure I would have added 3.5ml in that bottle. From the picture it looks like there is 0 empty space, which will make it harder to swirl to fully dissolve. If it still hasn't fully dissolved, you could try drawing 0.5 ml out of the bottle to create some more space for the liquid to move around and dissolve. Then transfer/filter it into a new sterile vial.
For ghk-cu, I recon with 3ml then filter into a new larger sterile vial and add additional bac to dilute it more. My last bottle was 100mg, so I filtered into a 10ml bottle and added another 7ml of bac. Giving me 1mg/10iu and no sting.