Hello,
Thanks for posting your query at DoctorSpring.com
I am Dr.R.K and I am pleased to assist you.
There are many different causes of blood in stools.
Some of the common causes are hemorrhoids, anal fissure, colitis, divesrticulosis and malignancy.
Since this occurred after a short period of constipation, the most likely cause is acute anal fissure.
You need to take high fiber diet, take stool softeners, drink lot of fluids and do sitz bath. Sitz bath is done by sitting in a tub of warm water exposing your rear part for 5-10 minutes 2-3 times a day.
You can consult your doctor for a rectal exam to confirm this and may undergo sigmoidoscopy test to rule out other causes.
I hope that answers your query.
Let me know if I can assist you further.
Regards,
Dr.R.K.