Whenever you're working with big thin sheets of glass there's always the possibility of breaking something; it's one of the hazards of these kind of DIY repairs. However, in this case it doesn't look to me like a cracked LCD from being flexed during removal or installation.
My guess would be either possible damage to the LCD cable or the TAB connectors that connect the flex cable to the LCD glass, but it doesn't necessarily have to be that bad. I'd say the first thing you need to check is the display cable plugging into the LCD panel; those FPC connectors can sometimes be a little tricky to get in all the way so there's a possibility it's just not seated all the way and that's what you're seeing.
Of course, the problem is you're going to have to open the whole thing back up again in order to check it. Once you get there, unplug it then check both sides of the connector, both on the LCD and on the flex cable, looking for any bent, broken or missing pins; a magnifying glass and a bright light are recommended for that. Bent pins can sometimes be straightened with fine tip tweezers but broken or missing pins are a much bigger problem. Also check the length of the flex cable for any scratches or tears in it.
Assuming everything looks good up to now, clean both sides of the connectors with 90% or higher concentration of isopropyl (rubbing) alcohol. Let it dry, plug everything back in and retest.
If you still have problems then yeah, there's a good chance the LCD got damaged and needs to be replaced; that's really the only fix you can do in a case like that, since LCDs themselves can't be repaired.
So open 'er up and double check all the connectors that got unplugged when you did the battery then come on back and let us know what you found.