My dog, a chihuahua shitzu mix (very tiny dog!), has bad diarrhea and a pink fleshy hemmroid looking thing. ??

i haven't noticed him scratching or dragging his or having any discomfort at any time but i had runny stool and i had to wash him and thats when i noticed that his rectum was all irritated and he has a hemmroid looking thing protruding from his rectum. i read online that if its hemmroids i can treat them as a human would treat them with cream but i also read that it could be tumors or signs of a more serious disorder. i just want to know if i need to take him in right away or if i can try to treat myself and monitor him for improvement. i would also like to compare to some pictures if possible for my own piece of mind. please help!! he's obviously a male and has just been recently nuetered, about 1 month ago, so maybe that plays into this problem. he also is on a steady solid food diet and does not recieve table scraps very often.