"Good" is an adjective. "Well" is normally an adverb but can be an adjective when it refers to health. So normally, only one of them is correct. However, when you are talking about health they are sometimes interchangeable: "Billy is not sick any longer. He feels well now." "Billy is not sick any longer. He feels good now."

This is an issue that will puzzle you, because the rules don't always fit the phrases we use. However, use 'very well' for when someone/something DOES something. 'The dog runs very well.' Use 'very good' for describing a noun. 'Your hair looks very good.' But, you will say, doesn't 'very good' refer to 'looks'? No, here refers to the hair. Take words like looks, is, have as words where your focus is the noun. Hope that helps!!:)

"Very well" is an adverb phrase that is often used to describe how something was done or how well an action was performed. "Very good" is an adjective phrase used to describe the quality, condition, or nature of something. Ex.) "The ice cream was very good" Ex.) "He speaks English very well"