Do you lose your upper lip after having an upper bridge on four front teeth?

If the bridge was fabricated properly you should have excellent lip support and excellent esthetics.  Were you happy with your temporary bridge that was in place during the fabrication of the permanent bridge?  If so the final bridge should have been made with similar dimensions.  I would definitely speak with your dentist regarding the issue and have him correct the situation if necessary

If the dental work has been done properly your replacement teeth should be positioned properly to support your upper lip.  I know that you said the teeth are much smaller than expected and you had no issues with your temporary so I would speak to your dentist about the concerns that you have

There should be no real change in lip position or profile after having a bridge in the front.  If anything it should improve.  Please discuss with your dentist especially if the temporary bridge was satisfactory - you may have to have the bridge replaced but if there is that much of a problem with the position, size/shape of the teeth, as well as speech, that may be the only option. 

If the dental work is being done by a true cosmetic dentist, your upper lip should be positioned properly after having an upper bridge done. Make sure you discuss your concerns with your dentist BEFORE beginning your treatment. He (she) should be able to show you before/after pictures of similar patients that he treated.