My recommendation is that you buy and hold for the long term and don't try to time the market in the short term. You can mark a few milestones to sell partially, though.
You talk about Ethereum. Have you studied it? Do you think it will be more valuable in 5, 10 years? If the answer is yes, Hold.
Yesterday I bought ETH worth of 160$ when it was worth 800$. Now it is over 1000$ and I know it's going to rise even more by the end of the month. Is it better to sell it now for 1000$ and buy back as much as or hold it by the end of the month? Which will make more profit? Thanks a lot!
With such a small sum, I would, as I said, hold, and I would try to add moremoney regularly. Trying to buy and sell with that small capital and the lack of knowledge you show, it will lead you in 99% of the cases to lose money.
I understand that you are maybe from a poor country or don't have much money, but if you've invested $160 that should be because you don't need them. Try to invest some more money you don't need until you gather a decent stash.
Buying and holding is more boring that trading short-term but it is more profitable in the vast majority of cases. Especially in your case.