If it’s dry, wet it!
If it’s wet, dry it!
If it looks weird…. Well, cut it off!
Here you will find dermatology learning resources.
http://www.everydayebm.org/naunheim-files/2016/8/22/a-skin-lesion-from-nigeria – An interesting skin lesion (no spoilers!), plus pictures and discussion of other conditions which may populate your differential.
http://www.emdocs.net/drug-rashes/ – Don’t do drugs, kids. Drugs cause rashes. This is what drug rashes look like.