Everyone above is giving a wrong explanation. Exacerbate makes no common sense at all for the first blank. I was looking for a word like better. Although other medicines make the pain better , to her dismay the medicine she applied made it worse.

Anyways, I double confirmed the answer from the book and it turns out, I was right. I will copy paste what is written in the book:




4. staved off, contributed to, and affliction

The clue “Although most medical, preventative ointments commonly in use” tells you that most ointments would prevent an infection, but the one Helen used did not. Recycle the clue, and put a word that means prevent in the first blank; staved off is the best match. Work with the second and third blanks together. The ointment did not prevent an infection, and the clue “much to her dismay” tells you that something bad happened. The only pair that makes sense together is contributed to and affliction because they tell you that the ointment made her problem worse.