Ask the immigration customs in Singapore.

Medicine can be taken, as long as it is not drugs or illegal things, it is generally not checked.

If spray liquid is used, it cannot be consigned 100ml, nor can it be put in the consignment box.

Generally, anything you are not sure about can be put in the inspection box. As long as it is not overweight, the inspection of that box can be ignored!

This is my experience in dealing with airports several times. I hope I can help you!