Cath getting another white chip is totally up to you. If you are not taking them as prescribed then you could consider it abusing them. Cath what ever you decide is your decision.
If you feel you messed up then I would say by all means pick up that chip, why let that eat at you? You did it, step up to the plate and get a chip, it can not harm you, more then likely you will gain from this in the long run.
Have you told the doctor who prescribed them you are an alcoholic? If you have not it may be a good idea, you should also mention that you did feel the need to take more then prescribed, he may prescribe you something else.