It's a risk you have to consider. Permanent side effects are very, very rare, unless you go into accutane with nutritional imbalances (like low vitamin D). No one can tell you that the dry eyes will 100% not be permanent. But from all of the anecdotes I've seen, it basically always reverts within a month after being off treatment. So will the red skin.
If I were in your position, I would push through. The length of treatment is more important than the dosage, and if you were going to get any permanent side effects, you would have gotten them by now. One more month, hell, three more months, are very unlikely to cause any more harm.