Here are two more photos. One of the "bulge" and another of a bad plaster crack. There seems to be some drywall tape along the ridge of the bulge.
Someone told me about Big Wally's Plaster Magic. I saw someone had a positive review about it. Would that help me here?
(Sorry, I did the photo upload incorrectly. I'll try to fix them)

Someone told me about Big Wally's Plaster Magic. I saw someone had a positive review about it. Would that help me here?
(Sorry, I did the photo upload incorrectly. I'll try to fix them)