Asalaamu Alaikum, Sister again the same rule applies. The tissue was wet with water and your cleaned yourself with it so therefore how can it make you impure again?
According to Sheikh Mufti Ebrahim Desai who answered a similar question to yours from someone who also suffered from waswas:
Undoubtedly, these doubts are from Shaytaan. You need to build confidence in yourself. The solution to your problem is simple. All it needs is ?will-power?. When you complete your Istinjaa like normal, be relaxed and comfortable and make yourself aware that you re clean and its over. All other ideas, doubts, thoughts and whispers are from Shaytaan. Ignore them.
Just continue like normal, make your Wudhu and complete your Salaat. Concentrate in your Salaat. Do not think about how you washed yourself during Salaat. Just think about the power and majesty of Allah Ta'ala. You have to build this confidence within yourself within yourself to remove these doubts. Also, make constant Du'aa to Allah Ta'ala to make it easy for you to concentrate in Salaat.
Source: http://www.islam.tc/cgi-bin/askimam/...=8954&act=view
Sister the ONLY solution to this is to get to the root of your problem. The root of your problems are not these minor cases that bother you so much but it is that you have no confidence in yourself and you lack will power and because of that the shaythan is taking advantage of you everyday.
Today your problem is this and tomorrow it will be something else. Shaythan will always find one way or another to get at you unless you build confidence within yourself and have enough will power to say NO! You have to force yourself NOT to listen shaythan as he is clearly trying to get at you with the most minor of things which seem to affect you so much.
You need to keep readind the advice i gave you in the other thread and apply it to your everyday life and also take action on the ruqya treatment for waswas aswell as continuing with OCD therapy. If you don't do something about this now then it will plague you for the rest of your life.
So take action sister and do not give up. Persevere and fight it and do not ever think it will defeat you because that is what shaythan wants you to think. You WILL defeat it but you have to strive and fight it until it is gone!
May you conquer this plague once and for all.