Pictures of PCBs are useless, especially when traces are hidden by solder resist paint. Don't bother posting them. Post a schematic.
Notice that the maximum current through one ATmega IO pin is only 40 mA. That means: if you want to switch on/off the LEDs from firmware then you may need to use a transistor to boost maximum output pin current.
You have more options:
* connect all LEDs in parallel (each LED will have its own resistor) - that means one led can use at most 300/68 ≅4 mA
* try to connect two LEDs in series and check how much current they take (if it is less than 8 mA and they are still bright enough) then you can connect blocks of LEDs in parallel; each block will have two LEDs in series (without any resistor), this allows you not to waste energy in resistors but it will be more sensitive to slight differences in LEDs
* use a LED driver IC, you need this option if you want to control brightness of each LED separately; there are hundreds of LED driver chips. select one and read its speciffication