Have anal tear, can it start to bleeding again after it stopped day before? can pain from it get worse when it wasn't too bad to begin with? and why?

Yes: The bleeding can be intermittent. Avoid hard bowel movements, take over the counter stool softener and soak your bottom in warm water for about 15-20 min. The pain can increase the spasm of the sphincter muscle which inturn can cause more pain specially during a bowel movement. If symptoms are not getting better you need an evaluation by your physician amd possibly referral to a colorectal surgeon.