Welcome to icliniq.com.
Let me tell you one thing, you need not worry about your condition, as it is widespread to have phimosis, which is the case with you. The foreskin is tight in your case, and hence, retraction is painful. The white patch you are referring to is nothing but color due to fibrosis. This has nothing to do with masturbation. You can undergo a simple procedure called circumcision, which will get rid of the foreskin and your problem with it, once for all.
It is a minor procedure. Please address the issue of hygiene better. Though there will not be any serious health issues with cleanliness, absence of hygiene can result in fungal infection, which can be avoided by addressing the hygiene properly. Let me reassure you again, and you need not worry much, go for circumcision.