What can I do to lower my blood pressure when it gets high after I've already taken my blood pressure medication?

Hmmm. You can try meditation / yoga / biofeedback types of stress reducers to see if they help. More likely, you should be keeping a BP diary (date/time and reading, also with entries for what time you take your med (s)), and then take this in to your doctor--you might be undermedicated, or on non-ideal medicine for you. Get a few days' worth of data and ask your doc.