What is the use of homeopathis medicine ricinus communis d4 ?

the doctor had asked me to go for ricinus communis 3 potency drops for low milk but i could not find it so i got ricinus mcommunis d4 drops. will it help in incereasing the milk supply. i take 4 drops in 1\4 cup of water after evey 4 hours. is it ok.i asked the doctor he told me that d4 is higher potency and aid that we want 3 potency but how ever we can use d4 too but he was like not sure.please advice.