It's pretty simple. Do you personally think that bitcoin will be worth more than that sometime in the future? If you think it will, then buy, regardless if it drops more or not. If you think it won't go up in the future, then don't buy. It's that simple.
I think this quote is something that everyone should consider, I don't mean to just follow this advice but it can help in making a decision, in the end, you will be the one who will make the decision.
By the way, my thoughts on buying dips is that you should assess yourself, are you looking for a quick buck? If yes, then you might decide not to buy that dip because that dip might plummet even lower. On the other hand, dips in the prices can be an oppurtunity for you to buy at lower prices and wait for the prices to go up and then at that time, you will gain considerable amount of profit if you plan to sell it. If you do not know when to sell then you can set a mental note that at this price you are going to sell it, that is what I am doing, I am still a student so I do not need the profit ASAP.
Remember that the decision will always fall in your hands, you might not follow all of this and that is okay, this advices are just mere testimonials on our experience, so no pressure.