Teruk is normally used for a situation while buruk is more appropriate to be used with a noun. But some time you may use teruk for noun if the thing you reffered at is really at bad condition.. most of the time the words are interchangeable... only use teruk when you find it really really bad... one more thing when you use the words to judge someone's look its more appropriate to use buruk if you mean the person is ugly.. u only can use teruk to refer the person facial condition after certain things happen that make the person face look terrible like after an accident. Example wajah dia kelihatan teruk selepas di serang seseorang . his/her face look terrible after being attack by someone.. off course you could have a good looking face before the incident :))