Hi thanks for your query.
You have rash on chest and neck, worse in the evening. Contact dermatitis
has been ruled out. Both verapamil and hydrochlorthiazide can cause a skin rash. Other possibility can be ring worm, folliculitis
You may consult your dermatologist
for examination to find out the exact cause.
If he feels that it may be due to verapamil or hydrochlorthiazide you may discuss it with your doctor for other substitute of these drugs, changing one at a time, it will help to know which drug is causing it.
Hope this helps you.