Hello!
Escalate: think of stairs, when something escalates it grows bigger progressively and gets to a point where one thing that was once so small has become so big it can't be controlled. "They were arguing about food and it escalated until they got into a physical fight."
Degenerate: when something degenerates, it becomes worse over time. Also, as a noun, a degenerate is someone who is depravate.
"The hurricane degenerated and destroyed some houses."
"That man is a degenerate without remorse."
Deteriorate: I'd say this rather refers to the physical or aesthetic state of someone or something. It becomes uglier or weaker over time.
"The façade has deteriorated throughout the centuries."
"Her health began to deteriorate when she turned 50."
Exacerbate: to make something worse.
"The weather is exacerbating the protests for animal rights."
Go downhill: when something goes so wrong that nothing can be done to make it better, it goes downhill.
"Her mental health went downhill after her brother's sudden death and she never recovered."
Go pear shaped: to go wrong.
"The test went pear-shaped."
I hope to have helped you!