Looks like scale insects to me, but hollyhocks also suffer very badly from rust which turns the leaves brown and causes them to fall. If you scratch off one of the little 'dots' and examine it under a magnifying glass, you should be able to see if it is a sap sucking insect or scale.
The treatment from these on a citrus plant is to dab them with methylated spirits but that would be an impossible task on a hollyhock. I would guess it would recover as the season advances and new leaves form, alternatively you could spray it with a systemic insecticide if you don't mind putting poisons on your garden.

If this is rust, and it might be, there should be corresponding yellow or brown dots on the upper leaf surface. If they are present, spray with a fungicide that treats for rust.

Many thanks for your help and the picture I sent was of the back of the hollyhock leaf and there are yellow dots on the top of the leaves so maybe it is rust I will spray with some fungicide and see if that helps once again thankyou all for your help

Spray under the leaves as well as the tops, and the stems of the plant. Remove any fallen leaf debris from the base. Spray regularly, preferably with a systemic fungicide, follow the use instructions on the container - rust is a big issue on hollyhocks, so control is the only option.

Thankyou I will do all those things you have suggested